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MOSQUITO  ERADICATION 


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PUBLISHERS     OF     BOOKS      FOIL/ 

Electrical  World  v  Engineering  News -Record 
Power  v  Engineering  and  Mining  Journal-Press 
Chemical  and  Metallurgical  Engineering 
Electric  Railway  Journal  v  Coal  Age 
American  Machinist v  Ingenieria  Internacional 
Electrical  Merchandising  v  BusTransportation 
Journal  of  Electricity  and  Western  Industry 
Industrial  Engineer 


MOSQUITO  ERADICATION 


BY 

W.  E.  HARDENBURG 

SANITARY    ENGINEER 
CERTIFIED    MEMBER,    AMERICAN    ASSOCIATION    OF    ENGINEERS 


First  Edition 


McGRAW-HILL  BOOK  COMPANY,  Inc. 
NEW  YORK:  370  SEVENTH  AVENUE 

LONDON:  6  &  8  BOUVERIE  ST.,  E.  C.  4 

1922 


I'l3 


Engineering 
Library 


Copyright,  1922,  by  the 
McGraw-Hill  Book  Company,  Inc. 


Ci'Ji'l    ley Zi '*££'*'  ^9     UtfJ~> 


THE    MAPLE    PRESS      -      YORK    PA 


PREFACE 

Along  with  the  marked  increase  in  public  appreciation  of 
preventive  medicine,  that  has  developed  in  recent  years  in  the 
United  States,  has  come  a  recognition  of  the  great  importance 
of  mosquito  eradication,  particularly  in  the  South.  This  has 
manifested  itself  in  the  launching  of  anti-mosquito  campaigns  in 
cities,  towns  and  villages  in  every  Southern  State,  and  it  is  a 
foregone  conclusion  that  the  success  of  these  will  spur  other 
communities  on  to  action. 

Abroad,  too,  the  menace  of  the  mosquito-borne  diseases  is 
being  recognized.  In  the  tropical  and  sub-tropical  areas  of 
Latin-America,  the  International  Health  Board  of  the  Rockefeller 
Foundation  has  done,  and  is  doing,  very  valuable  work.  Many 
American  corporations  employing  labor  in  those  regions  have 
found  that  it  pays  to  protect  their  labor,  and  are  doing  so. 
Furthermore,  the  governments  of  many  of  the  Latin-American 
countries  are  awakening  to  the  heavy  toll  of  the  mosquito- 
borne  diseases,  and  are  taking  steps  to  eradicate  them. 

The  same  may  be  said  of  many  regions  in  Europe,  Asia  and 
Africa.  Anti-mosquito  work  now  is  being  carried  on  to  a  greater 
or  lesser  extent  in  Italy,  Spain  and  several  of  the  Balkan  coun- 
tries; in  Mesopotamia,  India,  Ceylon,  the  Malay  Peninsula  and 
many  Pacific  islands;  in  East  and  West  Africa,  Madagascar  and 
various  other  political  subdivisions. 

This  means  that,  in  the  aggregate,  an  enormous  volume  of 
anti-mosquito  work  is  being  done  today.  And,  as  the  fruits  of 
this  work  become  better  known  and  appreciated,  it  will  increase 
many  fold  in  all  the  above-mentioned  countries.  Furthermore, 
as  other  territories,  that  are  today  undeveloped,  awake,  more 
anti-mosquito  work  will  have  to  be  done,  if  man  is  to  exploit 
their  resources  efficiently. 

This  vast  volume  of  work,  both  present  and  prospective, 
renders  it  incumbent  that  only  the  best  methods  should  be 
employed.  While  many  persons  may  have  a  general  idea  as  to 
the  procedure  in  mosquito  eradication,  this  is  not  sufficient  for  the 


567449 


vi  PREFACE 

men  in  charge  of  the  work.  They  must  know  what  methods  are 
best  adapted  to  the  particular  problem  they  have  in  hand,  or,  in 
other  words,  what  is  the  cheapest  way  of  accomplishing  the 
desired  result.  In  anti-mosquito  work,  as  in  other  branches  of 
engineering,  the  goal  should  be  to  get  the  best  results  for  the 
money  available.  If  the  cost  of  eradicating  mosquitoes  is  to 
amount  to  as  much  as  the  toll  of  the  mosquito-borne  diseases, 
but  little  is  gained. 

Although  the  importance  of  this  matter  is  self-evident,  there 
seems  to  be  an  amazing  paucity  of  books  on  mosquito  control. 
When  the  writer  started  in  at  anti-mosquito  work,  about  the 
only  material  he  could  find  on  the  subject  was  stray  references 
to  it  in  medical  works,  various  pamphlets  published  by  Federal 
and  State  health  and  agricultural  organizations  and  LePrince 
and  Orenstein's  valuable  volume.  "Mosquito  Control  in 
Panama,"  which,  however,  deals  with  work  under  somewhat 
exceptional  conditions. 

So  far  as  the  writer  knows,  this  situation  still  obtains.  Asked 
repeatedly  for  the  name  of  some  text-book  on  mosquito  control, 
he  has  been  unable  to  mention  any  one  book,  with  the  exception 
of  LePrince  and  Orenstein's,  that  deals  adequately  with  the 
subject.  It  is  with  a  view  to  supply  this  deficiency  that  he  has 
prepared  the  present  volume. 

A  conscientious  effort  has  been  made  to  outline  the  best  prac- 
tice, both  in  the  United  States  and  abroad.  It  has  been  the 
special  aim  of  the  writer  to  be  concise,  so  as  to  avoid  making  the 
volume  too  bulky,  but  to  omit  nothing  of  value. 

The  writer  takes  pleasure  in  acknowledging  here  the  kindness 
of  Dr.  Harrison  G.  Dyar,  Director  of  the  U.  S.  National 
Museum,  in  revising  part  of  the  chapter  on  mosquitoes;  of 
S.  F.  Hildebrand,  Ichthyologist,  in  revising  the  chapter  on  fish 
control;  and  of  W.  A.  Hardenbergh,  Sanitary  Engineer,  in 
making  many  valuable  suggestions  regarding  the  book.  Credit 
is  given  writers,  from  whose  works  extracts  have  been  used, 
throughout  the  volume. 

W.  E.  Hardenburg. 
San  Diego,  Calif., 
June,  1922. 


CONTENTS 

Page 

Preface v 

CHAPTER  1.— The  Toll  of  the  Mosquito 1 

Diseases    spread    by    the    mosquito — Transmission    of    malaria — 

/  Characteristics  of  malaria — Distribution  of  malaria — Mortality 
and  morbidity  of  malaria — Economic  significance  of  malaria — ■ 
Malaria  as  a  labor  problem — Transmission  of  yellow  fever — 
Mortality  and  morbidity — Yellow  fever  versus  malaria  control — 
Dengue — Filariasis — Economic  significance  of  yellow  fever,  dengue 
and  filariasis — The  mosquito  as  an  annoyance;  effects  upon  health 
— The  mosquito  as  an  annoyance;  economic  significance — Increas- 
ing property  values. 

CHAPTER  2. — Some  Disease-bearinc  American'  Mosquitoes  .  .  17 
The  mosquito  in  general — Life-history  of  the  mosquito — Varia- 
tions in  eggs,  larvae  and  pupae — Why  mosquitoes  bite — Identifica- 
tion of  mosquitoes — Anatomy  of  the  mosquito — Anatomy  of  the 
larvae — The  Anophelinae — Identification  of  the  Anophelinae — 
A.  quadrimaculatus  Say — A.  crucians  Wied. — A.  punctipennis 
Say — A.  occidentalis  D.  &  K. — The  Culidnae — Aedes  calopus  Meig 
—Culex  jatigans  Wied.. — -Some  common  troublesome  mosquitoes — 
House  group — Fresh-water  sylvan  group — Salt  marsh  group. 

CHAPTER  3. — Development  of  Control  Measures 50 

Historical  aspects — Beginning  of  mosquito  control — Sanitary 
conquest  of  the  Canal  Zone — Anti-mosquito  work  elsewhere — 
Malaria  control  in  U.  S. — -Interpreting  results — Early  U.  S.  malaria 

^  control  demonstrations — Demonstration  at  Electric  Mills,  Miss. — 
Co-operative  demonstration  at  Crossett.  Ark. — Work  of  St. 
Louis  &  Southwestern  Railroad — U.  S.  Anti-mosquito  work 
during  world  war — 43  war-project  areas  protected — Post-war 
mosquito  control — The  situation  today — Change  in  public  view- 
point— Growth  of  appreciation — Eradication  cheaper  than 
enduring  malaria — Some  typical  campaign  costs. 

CHAPTER  4. — Initiating  the  Campaign 66 

Need  for  statistics — Collection  of  statistics — The  survey — What  to 
observe — The  estimate  of  cost — Questions  of  policy — Suggested 
policy  toward  property-owners — Raising  funds — Handling  the 
funds — Obtaining  co-operation — Other  possible  sources  of  aid — 
Planning  the  work — Personnel — Materials  and  equipment. 

CHAPTER  5. — Administrative  Aspects  of  the  Campaign 83 

Mosquito-breeding  about  homes — Planning  the  inspection  system 
— Handling  the  negligent  citizen — Complaint  bureau — Publicity — 

vii 


vili  CONTENTS 

Page 

Texts  for  articles — Other  methods  of  obtaining  co-operation — 
Daily  reports — -Records — Maps. 

CHAPTER  6.— Inland  Drainage 99 

Importance  of  drainage  as  an  anti-mosquito  measure — Limitations 
of  drainage — Preliminary  work — Types  of  inland  drainage  prob- 
lems— Problem  of  pond,  lake  and  swamp  drainage — Treatment  of 
seepage  outcrops — Drying  up  a  swamp — Ditch  construction  in 
general — Hand  ditching  on  firm  ground — Cost  of  ordinary 
hand  ditching — Hand  ditching  in  swamps — Blasting  ditches 
in  swamps — Making  trial  shots — Cleaning  out  the  ditch — Ad- 
vantages of  blasting  ditches — Machine  ditching — Some  typical 
open-ditching  machines — Maintenance  of  open  ditches — The  weed 
burner — Maintenance  costs — Permanent  lining  of  anti-mosquito 
ditches — -Sub-surface  tile  drains — Tile  drains  versus  open  ditches 
— Laying  out  a  tile  drainage  system — Placing  the  tile — Tile 
drainage  costs— Vertical  drainage — Typical  vertical  drainage 
operation — Vertical  drainage  for  large  areas — Stream  re-chan- 
eling — Blasting  new  channels — Clearing  streams  of  logs,  etc. — ■ 
Filling. 

CHAPTER  7.— Salt  Marsh  Drainage 139 

The  salt  marsh  problem  in  general — Agricultural  "\  ersus  anti-mos- 
quito drainage  of  salt  marshes — Design  of  salt  marsh  ditches — Salt 
marsh  ditching  by  hand — Machine  ditching — Filling — Diking  and 
tide-gating  in  general — Constructing  the  dike — -The  tide-gate  and 
sluice-box — Construction  of  sluices — Gate  construction — Specifi- 
cations for  large  sluices — Installation — Other  types  of  tide-gates 
— The  Calco  gate — Operation  of  tide-gates — Salt  marsh  shrinkage 
— Pumping. 

CHAPTER  8.— Oiling 158 

Place  of  oiling  in  anti-mosquito  work — Where  oiling  is  applicable — 
Applying  the  oil — Kind  of  oil  required — Larvicides — The  Panama 
larvicide — Other  larvicidal  substances — The  sprayer — Drip-cans — 
Use  of  drip-cans — Other  methods  of  applying  oil — Frequency  of 
oiling — Distribution  of  oil — Storage  of  oil — Costs  of  oiling. 

CHAPTER  9.— Fish  Control 172 

Advantages  and  limitations — How  fish  destroy  larvae — The  top 
minnow  (Gambusia  affinis) — The  barred  killifish  (Fundulus  hetero- 
clitus) — The  striped  killifish  {Fundvlus  majalis) — -The  fresh-water 
killy  (Fundulus  diaphanous) — The  variegated  minnow  (Cyprinodon 
variegatus) — The  rain-water  fish  (Lucania  parvia) — The  spotted 
top  minnow  (Fundulus  notatus) — The  star-headed  minnow  (Fun- 
dulus notii) — Other  fishes — Procedure  in  fish  control — -Number 
of  fish  required — Distributing  the  fish — Necessity  of  aiding  the 
fish — Plants  in  relation  to  fish  control — Eliminating  larva-pro- 
tecting plants — The  sub-aqueous  saw — Using  the  saw. 

CHAPTER  10.— Screening 195 

Place  of  screening  in  anti-mosquito  work — Rarity  of  good  screen- 


CONTENTS  ix 

Page 

ing — Essentials  of  good  screening — Screening  of  doors — Some 
general  rules — Screening  of  windows — Screening  of  porches — 
Screening  of  chimneys  and  fire-places — -The  life  of  a  screen — 
Screening  near  the  sea-side — Conducting  a  screening  campaign — 
Value  of  screening — Cost  of  screening — Does  screening  pay? 

CHAPTER   11. — Other    Measures    and   Expedients   and   Points 

Requiring  Investigation 209 

Scope    of    this    chapter — Auxiliary    methods    and    expedients    in 
general — Direct  exterminative  measures — The  bat  as  a  destroyer 
of    adult    mosquitoes — Other    animal    foes    of   the    mosquito— 
^-  Destruction  of  mosquitoes  in  dwellings — Harassing  the  mosquito 

— Further  protective  measures — Use  of  animals  as  a  protection 
against  mosquitoes — Application  of  substances  repellent  to  mos- 
quitoes— Use  of  quinine  for  malaria — Demonstrations  of  the  value 
of  mass  treatment  by  quinine — Quinine  versus  anti-mosquito 
measures — Points  that  require  further  investigation. 

CHAPTER  12.— Rural  Mosquito  and  Malaria  Control  .  .  .  .219 
Unfavorable  factors  in  rural  control — Favorable  factors  in  rural 
control — Need  for  a  survey — Control  measures  about  the  average 
home — Further  measures — Protecting  homes  in  swamps,  etc. — 
The  rice-field  problem — The  rice-field  problem  abroad — Com- 
munity measures  in  rural  areas — 'Rural  community  protective 
demonstrations. 

APPENDIX  A. — Table  to  Determine  Species  of  Certain  Common- 
American  Mosquitoes 228 

APPENDIX  B. — Approved  Anti-mosquito  Ordinance 233 

APPENDIX  C. — Suggested  Anti-mosquito  Leaflet  for  Campaic-n 

Educational  Work 235 

APPENDIX  D.— Bibliography 238 

INDEX 241 


MOSQUITO  ERADICATION 

CHAPTER  I 

THE  TOLL  OF  THE  MOSQUITO 

DISEASES  SPREAD  BY  THE  MOSQUITO 

While  much  has  been  accomplished  in  recent  years  in  diffusing 
information  as  to  the  preventability  of  the  mosquito-borne 
diseases,  it  is  very  doubtful  if  the  public  yet  has  an  adequate  idea 
of  the  mortality,  suffering  and  loss  they  occasion  and  of  the 
general  feasibility  and  direct  economic  advantage  of  mosquito 
eradication. 

The  toll  of  the  mosquito  may  be  regarded  from  three  aspects- 
first,  the  annoyance,  suffering  and  death  caused  by  the  diseases 
it  transmits;  second,  the  economic  loss  resulting  from  these 
diseases  in  expenditures  for  medical  aid,  nursing  and  medicines 
and  in  loss  of  time  and  productive  energy;  and,  third,  the  eco- 
nomic loss  it  occasions  by  holding  back  development  of,  and 
depressing  property  values  in,  sections  where  it  abounds. 

Apart  from  the  discomfort  and  vexation  it  causes,  the  mosquito 
is  the  transmitting  agent  of  no  fewer  than  four  distinct  diseases — 
malaria,  yellow  fever,  dengue  and  filariagjs-  Of  these,  malaria 
and  yellow  fever  are  of  the  very  first  importance. 

TRANSMISSION  OF  MALARIA 

Malaria  is  caused  by  three  separate  blood  parasites  or  heina- 
tocytozoa,  Plasmodium  malariae  (Laveran),  Plasmodium  vivax 
(Grassi  and  Filetti)  and  Plasmodium  falciparum  (Welch). 
These  produce  respectively  quartan,  tertian  and  estivo-autumnal 
or  tropical  malaria,  all  having  the  same  etiology  and  mode  of 
transference,  despite  well-defined  clinical  differences. 

It  is  now  well  established  that  malaria  is  transmitted  in  nature 
only  by  the  bite  of  the  Anopheles  mosquito,  this  mosquito  being 
the  only  animal,  other  than  man,  which  carries  the  malaria 
parasites.  The  mosquito  is  the  definitive  host  and  man  the 
intermediary  host,  both  being  necessary  to  complete  the  life 
cycle  of  the  parasite,  which  is  as  follows. 

1 


2  MOSQUITO  ERADICATION 

When  man  is  infected,  a  non-sexual  cycle,  known  as  schizogony, 
begins,  which  takes  from  48  to  72  hours.  The  sporozoite  bores 
into  a  red  cell,  becomes  round,  increases  in  size  and  finally  divides 
into  a  number  of  sporozoites,  each  of  which  repeats  this  process. 


Fig.   1. — The  malaria  parasite  and  its  life  cycle.      (After  John  B.  Smith,  New 
Jersey  Agricultural  Experiment  Stations.) 

Anopheles  Mosquito  and  Malaria:  A,  larva;  B,  pupa;  O,  adult;  D,  the  blast- 
introduced  into  the  blood  by  the  mosquito;  E  to  J,  stages  through  which  the 
Plasmodium  passes  in  the  red  blood  corpuscles;  K,  the  spores,  which  enter  new 
blood  corpuscles;  L,  M,  the  microgamete;  N,  O,  the  macrogamete;  P,  flagellae 
forming;  V,  union  of  a  flagellum  with  a  macrogamete;  R,  fusion  of  nuclei;  S, 
the  vermicule;  T  to  Y,  formation  of  the  zygote  in  the  stomach  of  the  mosquito, 
the  fully  developed  zygote,  Y,  rupturing  to  produce  blasts. 


In  about  2  weeks,  the  sporozoites  become  so  numerous  that  the 
toxin  liberated  at  each  division  is  sufficient  to  cause  chills. 
Eventually,  sexual  forms  appear,  the  females  being  known  as 
macrogametes  and  the  males  as  microgametocytes.     When  the 


THE  TOLL  OF  THE  MOSQUITO 


Q  ©  O 


Fig.  6. — Stomach  of  mosquito  with  oocysts. 
(After  Craig.) 


Fig.  2. — Parasites  of  tertian  malaria. 
(After  Thayer  and  Hewetson.) 


Fig.  3. — Parasites  of  estivo- 
autumnal  malaria.  (After 
Thayer  and  Hewetson.) 


Fig.  4. — Parasites  of  quartan  malaria. 
(After  Thayer  and  Hewetson). 


mB>, 


s 


Fig.   7. — Sporozoites   in   oocyst. 
After    Craig.) 


Fig.  5. — Fertilized  female 
malaria  parasite  (zygote)  ■ 
(After  Craig.) 


Fig.  8. — Sporozoites 
(After  Craig.) 


4  MOSQUITO  ERADICATION 

mosquito  bites  a  person,  these  forms  enter  its  stomach,  where 
they  combine  to  form  zygotes.  The  zygotes  divide  into  sporo- 
zoites,  which  finally  appear  in  the  salivary  glands  of  the  Ano- 
pheles. From  here  they  enter  the  blood  of  the  person  bitten  by 
the  mosquito  and  start  again  on  the  non-sexual  cycle. 

CHARACTERISTICS  OF  MALARIA 

It  is  noteworthy  that  it  requires  about  12  days  after  entering 
the  body  of  the  mosquito  before  the  sporozoites  appear  in  its 
salivary  glands.  This  means  that  the  mosquito  cannot  transmit 
malaria  until  12  days  after  it  has  bitten  a  malaria  patient.  The 
parasite  does  not  seem  to  injure  the  mosquito,  which  may  live 
many  weeks  and  infect  several  persons  successively.  A  mean 
temperature  of  less  than  60°F.  inhibits  development  of  the 
parasite  in  the  mosquito. 

"A  person  who  once  has  had  malaria,"  says  Rosenau,1  "is  more  apt  to 
have  subsequent  attacks.  Ordinarily  there  is  an  increased  susceptibility 
rather  than  an  immunity.  However,  repeated  infections,  especially 
during  early  life,  leave  a  very  pronounced  resistance.  In  malarious 
regions  many  children  carry  the  parasites  in  their  circulating  blood 
without  any  manifestations  of  the  disease.  These  carriers  are  important 
factors. in  spreading  the  infection  in  endemic  areas,  and  must  be  taken 
into  account  in  preventive  measures. 

"There  is  no  true  racial  immunity  in  this  disease.  Occasionally  a 
congenital  immunity  seems  to  be  transmitted ;  this  must  be  rare.  Practi- 
cally all  persons  who  receive  the  infection  for  the  first  time  are  sus- 
ceptible. The  freedom  from  malaria  which  some  persons  seem  to 
enjoy  may  be  accounted  for  partly  by  the  fact  that  mosquitoes  seldom 
bite  such  persons.  It  is  well  known  that  on  account  of  the  odors,  or 
what  not,  mosquitoes  do  not  bother  certain  individuals.  No  doubt  the 
infection  of  a  small  number  of  parasites  is  often  overcome  largely  through 
a  vigorous  phagocytosis. 

"Individual  resistance  varies  in  different  individuals  and  in  the  same 
individual  at  different  times.  The  parasite  may  remain  latent  in  the 
spleen  and  other  organs  for  years.  Exposure,  over-eating,  fasting, 
overwork,  or  worry,  or  anything  that  lowers  the  vitality  of  such  indi- 
viduals predisposes  to  an  attack  of  malaria.  The  disease  often  breaks 
out  in  persons  in  good  health  leaving  a  malarial  region  for  a  health 
resort,  whether  mountain  or  seashore." 

1  "Preventive  Medicine  and  Hygiene,"  New  York  and  London,  1918. 


THE  TOLL  OF  THE  MOSQUITO  5 

DISTRIBUTION  OF  MALARIA 

Trask1  sums  up  the  distribution  of  malaria  in  the  United 
States  as  follows : 

"In  the  territory  extending  from  the  Gulf  of  Mexico  to  a  line  north  of 
the  Ohio  River  and  from  the  Atlantic  seaboard  to  and  into  the  eastern 
part  of  Kansas,  Oklahoma  and  Texas,  few,  if  any,  localities  are  entirely 
free  from  malaria.  In  most  of  the  lowlands  it  is  very  prevalent;  in  the 
mountains  and  better  drained  areas  less  prevalent. 


Fig.  9. — Endemic  areas  of  malaria  in  the  United  States.  Shaded  portions  of 
map  show  endemic  areas.  Shaded  circles  represent  localities  in  which  cases  of 
malaria  occur  and  in  which  the  disease  is  probably  endemic.      (After  Trask.) 


'  The  disease  is  also  endemic  in  southeastern  Xew  York  and  parts 
of  Connecticut,  Rhode  Island  and  Massachusetts,  and  in  California 
in  the  Sacramento  and  San  Joaquin  valleys. 

"There  is  probably  no  state  in  the  Union  in  which  the  disease  is  not 
present  and  in  which  it  is  not  spread  by  mosquitoes  grown  locally. 

"The  disease  constitutes  one  of  the  big  national  health  problems. 
It  is  also  an  economic  problem  of  importance." 

Elsewhere,  malaria  is  found  in  nearly  every  country,  its 
incidence  increasing,  as  a  rule,  with  proximity  to  the  Equator. 


i— 


'"Malaria,    A   Public    Health   and   Economic    Problem   in    the    United 
States,"  U.  S.  Public  Health  Service,  1917. 


6  MOSQUITO  ERADICATION 

MORTALITY  AND  MORBIDITY  OF  MALARIA 

Sir  Ronald  Ross,  discoverer  of  the  transmission  of  malaria 
by  the  mosquito,  says: 

"Malarial  fever  is  perhaps  the  most  important  of  human  diseases, 
and,  though  it  is  not  often  directly  fatal,  its  wide  prevalence  in  almost  all 
warm  climates  produces  in  the  aggregate  an  enormous  amount  of  sick- 
ness and  mortality." 

"Malaria,"  says  Leathers,1  "is  the  most  prevalent  disease  in  all 
semi-tropical  and  tropical  countries.  It  is  the  most  frequent  cause  of 
sickness  and  death  in  those  parts  of  the  world  that  are  most  densely 
populated.  It  is  also  the  most  prevalent  disease  in  the  United  States, 
and  at  least  two-thirds  of  the  cases  found  in  this  country  occur  in  the 
Southern  States. 

''Malaria  is  one  of  the  greatest  scourges  inflicted  upon  humanity. 
It's  a  menace  to  any  people  or  country  in  which  it  has  a  decided  inci- 
dence. In  the  number  of  deaths  caused  either  directly  or  indirectly 
the  sickness  and  suffering,  the  loss  of  time  and  efficiency,  the  expense, 
the  lowered  vitality  of  those  afflicted  and  in  the  reduction  of  the  valua- 
tion of  property,  malaria  is  without  a  rival  among  the  diseases  afflicting 
mankind. 

"A  careful  investigation  shows  that  about  15,000  people  die  directly 
from  malaria  each  year  in  the  United  States.  This  does  not  take  into 
consideration  the  indirect  effects  of  the  disease  and  the  consequent 
mortality  assigned  to  other  causes,  which,  in  reality,  malaria  is  respon- 
sible for  in  large  measure.  In  addition  to  the  mortality  accruing  from 
malaria,  there  are  from  1,500,000  to  3,000,000  people  in  the  United 
States  sick  from  this  disease  annually." 

Carter2  estimates  the  annual  morbidity  from  malaria  in  the 
United  States  at  6,000,000  to  7,000,000. 

Rose3  estimates  that  in  India  malaria  causes  on  the  average 
each  year  about  1,130,000  deaths  and  more  than  100,000,000 
cases  of  illness. 

Hoffman4  gives  the  mortality  from  malaria  in  certain  other 
countries  during  designated  periods  as  follows: 

1  The  Importance  of  Malaria  from  a  Public  Health  and  Economic  Stand- 
point, Southern  Medical  Journal,  August,  1918. 

2  "The  Malaria  Problem  of  the  South,"  U.  S.  Public  Health  Service,  1919. 

3  Field  Experiments  in  Malaria  Control,  Journal,  American  Medical 
Association,  Nov.  8,  1919. 

4  "A  Plea  and  A  Plan  for  The  Eradication  of  Malaria,"  Prudential 
Insurance  Company  of  America,  1917. 


THE  TOLL  OF  THE  MOSQUITO 


Country 


Period 


Aggregate 
population 


Deaths 


Rate  per 
100,000 


Mauritius 

Nicaragua 

British  Honduras.  . 
Straits  Settlements. 

British  Guiana 

Philippine  Islands  . 

Venezuela 

Panama  Canal  Zone 

Porto  Rico 

Costa  Rica 

Ceylon 

Cuba 

Spain 

Italy 


1910-14 
1908-11 
1914-15 
1910-14 
1911-15 
1909-13 
1908-12 
1911-15 
1911-15 
1911-15 
1910-14 
1910-14 
1906-10 
1909-13 


1 

2, 


3, 
1 


,842,561 

180,000 

83,268 

,596,554 

516,710 

29,472,283 

13,525,191 

677,792 

4,675,044 

1,999,545 

20,817,228 

11,561,416 

96,717,000 

173,356,885 


21,686 

15,859 

491 

19,818 

6,385 

117,139 

41,331 

949 

3,793 

1,251 

11,304 

2,535 

10,930 

17,399 


1,176.9 

727.5 

589.7 

551.0 

421.0 

397.5 

305.6 

140.0 

81.1 

62.6 

54.3 

21.9 

11.3 

10.0 


ECONOMIC  SIGNIFICANCE  OF  MALARIA 
"It  is  not  in  the  death-rate,  however,  that  the  gravest  injury 
of  malaria  lies,"  declares  Carter.1 

"It  is  in  its  sick-rate;  in  the  loss  of  efficiency  it  causes,  rather  than  in 
the  loss  of  life.  One  death  from  pneumonia  should  correspond  to  about 
125  sick-days — work-days  lost;  one  from  typhoid  fever  to  400  to  500 
sick-days;  one  from  tuberculosis  to  somewhat  more  than  this  among 
whites,  decidedly  less  among  negroes.  A  death  from  malaria,  however, 
corresponds  to  from  2,000  to  4,000  sick-days.  This  loss  of  efficiency 
may  really  be  doubled  or  trebled,  for  the  man  infected  with  malaria  is 
frequently  half  sick  all  the  time. 

"And  it  is  the  amount  of  malaria,  when  it  is  bad,  which  appalls. 
If  1  per  cent  of  the  population  is  stricken  with  typhoid  fever,  it  is  an 
epidemic,  and  a  bad  one.  Contrast  this  with  40  per  cent  to  60  per  cent 
of  a  population  per  annum  affected  with  malaria,  and  I  have  seen 
outbreaks  with  90  per  cent,  and  you  gain  some  idea  of  the  importance 
of  this  disease.  The  loss  of  efficiency  caused  by  malaria  in  the  malari- 
ous section  of  the  South  is  beyond  comparison  greater  than  that  caused 
by  any  other  disease,  or  even  by  any  two  or  three  diseases  combined, 
including  typhoid  fever  and  tuberculosis. 

"lam  not  speaking  at  random.  You  have  never  heard  of  the  preva- 
lence of  typhoid  determining  the  failure  to  locate  industrial  plants. 
Yet,  at  one  place  where  power  was  abundant  and  very  cheap,  the 
manager  told  me  that  a  number  of  options  for  cotton  mills,  wagon 
factories,  etc. — options  which  had  been  taken  because  of  the  cheapness 
of  the  power — had  been  abandoned  because  of  the  prevalence  of  malaria. 

1  The  Malaria  Problem  of  the  South,"  U.  S.  Public  Health  Service,  1919. 


L- 


/ 


8  MOSQUITO  ERADICATION 

Has  the  presence  of  tuberculosis  ever  prevented  a  real  estate  transaction? 
I  know  of  a  deal  involving  the  purchase  of  large  tract  of  land  for  coloniza- 
tion— a  tract  valued  at  about  half  a  million  dollars — not  consummated 
on  account  of  the  prevalence  of  malaria  in  that  section,  and  there  was 
not  much  malaria  either.  You  have  not  seen  homes  abandoned  because 
of  either  tuberculosis  or  typhoid  fever.  I  can  assure  you  that  I  have 
seen  them  abandoned  on  account  of  malaria." 

MALARIA  AS  A  LABOR  PROBLEM 

"It  is  not  going  too  far,"  says  Hoffman,1  "to  say  that  malaria 
eradication  is  essentially  a  labor  problem  of  the  first  importance; 
that  an  enormous  amount  of  labor  inefficiency  due  to  malaria 
continues  to  hinder  the  progress  of  semi-tropical  and  tropical 
countries,  which,  if  brought  under  control  and  completely  done 
away  with,  must  needs  assist  profoundly  in  the  reclamation  of  the 
tropical  regions  for  the  practical  needs  of  the  world  at  large." 

An  interesting  investigation  of  the  losses  occasioned  by  malaria 
in  the  cotton-growing  section  of  Louisiana  was  made  by  Van 
Dine  of  the  U.  S.  Department  of  Agriculture.  The  work  involved 
a  detailed  study  of  the  malaria  morbidity  among  74  tenant 
families,  comprising  299  persons,  men,  women  and  children,  on  a 
typical  plantation.  There  developed  from  May  to  October 
inclusive  166  cases  of  malaria  in  138  persons,  causing  a  total  loss 
of  time  of  1,066  adult  days  or  6.42  adult  days  per  case.  This 
was  equivalent  to  loss  of  the  entire  working  time  of  5.54  families. 
Reduction  of  efficiency  of  the  workers  amounted  to  a  loss  of 
time  of  9.25  families,  making  a  total  loss  of  time  of  14.79  families. 
In  other  words,  60  families  would  have  done  the  same  amount  of 
work,  had  there  been  no  malaria,  as  74  families  did  with  malaria. 
Reduced  to  money,  it  was  found  that  the  actual  loss  of  time 
amounted  to  $2,200  and  loss  of  efficiency  to  $4,300,  making 
a  total  financial  loss  due  to  malaria  of  $6,500. 

From  these  figures,  it  will  be  noted  that  a  community  of  less 
than  300  persons  could  well  have  afforded  to  spend  up  to  $5,000 
to  $6,000  in  anti-mosquito  work,  while  an  investment  of  less 
than  $3,500  would  have  returned  a  dividend  of  100  per  cent. 


TRANSMISSION  OF  YELLOW  FEVER 

Although  the  cause  of  yellow  fever  is  not  definitely  known, 
the  infective  agent  being  apparently  ultramicroscopic,  the  manner 

1  "A  Plea  and  A  Plan  for  The  Eradication  of  Malaria,"  Prudential 
Insurance  Company  of  America,  1917. 


THE  TOLL  OF  THE  MOSQUITO  9 

of  transmission  is  well  understood.  It  is  now  definitely  estab- 
lished that  the  disease  is  conveyed  in  nature  only  through  the 
bite  of  an  infected  female  Aedes  calopus  mosquito. 

It  is  believed  that  the  mosquito  becomes  infected  by  biting 
persons  suffering  from  yellow  fever  during  the  first  3  days  of 
the  fever,  experiments  indicating  that  the  infective  principle 
disappears  from  the  blood  after  that  period.  The  mosquito, 
however,  is  unable  to  transmit  the  disease  until  about  12  days 
after  it  has  sucked  the  blood;  from  then  on,  it  remains  infected 
all  its  life  and  may  communicate  the  disease  to  several  persons 
successively. 

So  far  as  is  known,  man  is  the  only  animal  subject  to  yellow 
fever,  attempts  to  infect  other  animals  having  failed. 

The  fact  that  the  mosquito  can  be  infected  only  during  the  first 
3  days  of  the  disease  is  an  important  factor  in  prevention  of 
yellow  fever,  since  if  the  patient  can  be  isolated  from  mosquitoes 
during  this  period,  no  mosquitoes  will  be  infected  and,  hence, 
the  disease  cannot  spread.  Difficulty  in  diagnosing  yellow  fever 
sometimes  renders  this  impossible. 

Although  yellow  fever  has  been  a  scourge  for  centuries,  it  was 
not  until  1900  that  the  role  of  the  mosquito  in  transmitting  this 
dread  plague  was  ascertained  and  the  preventive  measures, 
based  thereon,  developed.  This  epoch-making  discovery  was 
made  by  a  board  of  American  army  medical  officers.  Previously, 
it  had  been  believed  that  the  infection  was  carried  in  clothing,  by 
the  air,  etc. 

MORTALITY  AND    MORBIDITY 

Although  yellow  fever  in  the  United  States  today  is  virtually 
eliminated,  the  terrible  epidemics  of  former  years  in  which  panic 
reigned  throughout  the  South  are  not  yet  forgotten.  In  South 
and  Central  America,  the  disease  is  still  epidemic  in  many  places, 
as  well  as  in  other  parts  of  the  world.  But  modern  medical  and 
engineering  science  is  routing  it  all  along  the  line. 

The  following  compilation  from  the  U.  S.  Public  Health  Service1 
reports  of  cases  occurring  in  various  North,  South  and  Central 
American  countries  during  the  fiscal  years  indicated,  is  admit- 
tedly incomplete  and  should  be  considered  only  as  an  indication 
of  the  areas  in  which  the  disease  is  more  or  less  endemic : 

1  Annual  Reports,  U.  S.  Public  Health  Service,  1918,  1919,  1920  and  1921. 


10 


MOSQUITO  ERADICATION 


Country 

1918 

1919 

1920 

1921 

Brazil 

2 

86 
1 
3 

13 

10 

61 

482 
56 

3 

32 

1 

3 

52 

1 

250 

57 

3 

Colombia 

Ecuador 

Honduras 

1 

Guatemala 

Mexico 

Panama  Canal  Zone 

11 
180 

Peru                                      

287 

Salvador 

Venezuela 

56 

YELLOW  FEVER  VERSUS  MALARIA  CONTROL 

While  the  same  principles  that  apply  to  the  prevention  of 
malaria  apply  to  the  prevention  of  yellow  fever,  prevention  of  the 
latter  is  by  far  the  easier.  In  the  first  place,  the  range  of  breeding 
places  of  Aedes  calopus  is  much  more  restricted  than  that  of  the 
Anopheles.  Again,  the  Anopheles  mosquito  flies  much  further 
than  does  Aedes  calopus.  Finally,  yellow  fever  patients  remain 
infective  for  only  3  days,  while  malaria  patients  carry  the 
parasites  sometimes  for  years. 

It  is  due  for  the  most  part,  probably,  to  the  last  factor  men- 
tioned that  yellow  fever  has  been  so  largely  eradicated  through- 
out the  United  States  today,  despite  the  fact  that  Aedes  calopus 
is  still  one  of  the  most  widely  distributed  of  the  Southern  mos- 
quitoes. In  other  words,  the  chief  reason  why  yellow  fever  is 
not  still  as  prevalent  in  the  South  today  as  malaria  is  because 
there  are  no  human  carriers.  When  an  infected  person  does  enter 
the  territory  of  Aedes  calopus  it  is  necessary  only  to  protect  him 
from  the  mosquito  for  3  days,  and  nobody  else  will  be  infected. 
With  malaria,  the  case  is  far  different ;  in  almost  every  community 
there  are  human  carriers,  who — unless  preventive  work  is  under- 
taken— are  bound  to  be  bitten  some  time  during  the  summer  by 
Anopheles  mosquitoes,  and  the  Anopheles,  of  course,  pass  on  the 
infection  to  other  persons. 

DENGUE 

This  disease  frequently  resembles  yellow  fever  in  its  epidemi- 
ology and  symptomatology,  and,  although  few  persons  have  ever 
died  of  it,  the  victim  often  is  left  in  a  more  or  less  disabled  condi- 
tion for  months. 


THE  TOLL  OF  THE  MOSQUITO 


1  1 


Dengue  is  believed  to  be  transmitted  by  Culex  fatigans, 
although  the  causative  factor  is  as  yet  unknown.  Graham1 
described  a  protozoon  which  he  believed  caused  the  disease,  but 
Ashburn  and  Craig2  assert  that  a  filterable  virus  is  responsible 
for  it.  They  placed  the  period  of  incubation  at  3  days  and  14 
hours. 

Dengue  somewhat  resembles  yellow  fever  in  its  rapid  com- 
municability,  sometimes  spreading  with  marvelous  rapidity  and 
infecting  virtually  every  person  within  its  vicinity.  Unlike 
yellow  fever,  however,  there  is  no  definite  immunity. 

The  prevalence  of  dengue  in  the  United  States  and  territories 
during  the  fiscal  years  1918  and  1919  is  reported  by  the  U.  S. 
Public  Health  Service  as  follows: 


1918 


1919 


States  and  territories 


Cases 


Deaths 


Cases 


Deaths 


Texas 

Louisiana . 
Colorado .  . 
California . 
Florida .  .  . 
Porto  Rico 
Hawaii .  .  . 


24 
4 

I 


127 

71 

1 

12 
345 


While  cases  of  dengue  in  the  United  States  are  comparatively 
few,  as  indicated  by  the  above  table,  it  is  certain  that  in  South 
and  Central  America  and  other  tropical  and  sub-tropical  coun- 
tries the  morbidity  from  this  disease  reaches  a  not  inconsiderable 
figure. 

FILARIASIS 

This  disease  consists  of  the  infestation  of  the  connective  tissues, 
lymphatics  and  body  cavities  of  man  with  larvae  or  adults  of 
filaria,  a  long,  slender  threadworm  with  a  curved  tail.  According 
to  Rosenau,3  none  of  the  young  worms  do  any  appreciable 
injury  to  the  blood,  while  of  the  adult  worms  only  one,  Filaria 

1  Journal  of  Tropical  Medicine,  vol.  6,  1903;  quoted  by  Rosenau. 

2  Philippine  Journal  of  Science,  May  1,  1907;  quoted  by  Rosenau. 

3  "Preventive  Medicine  and  Hygiene,"     New  York  and  London,  1918. 


12 


MOSQUITO  ERADICATION 


Fig.  10. — Mature  larvae  escaping  from  proboscis  of  Culex  fatigans;  one 
mature  larvae  coiled  in  base  of  proboscis.  From  mosquito  dissected  after  being 
infected  at  Charleston,  S.  C. 


THE  TOLL  OF  THE  MOSQUITO  13 

bancrofti,  which  causes  elephantiasis,  can  be  viewed  as  serious. 
These  worms  are  transmitted  to  man  by  mosquitoes,  Culex 
fatigans  apparently  being  considered  as  the  chief  offender. 

The  most  important  filariae  of  man,  according  to  Rosenau,1 
are: 

"  (1)  Filaria  bancrofti,  the  larva  of  which  is  known  as  Filaria  nocturna, 
appearing  in  the  blood  at  night  and  occurring  in  all  tropical  lands,  includ- 


*%4 


"•vast  ^ 


/ 
J 


L.  H.  WILDEIi 


Fig.  11. — Filariae  (without  sheath)  in  thoracic  muscles  of  Culex  fatigans, 
9  hours  after  ingestion  of  filarial  blood;  infected  at  Charleston,  S.  C.  Teased 
preparation. 

ing  America;  (2)  Filaria  loa,  the  larva  of  which  is  known  as  Filaria 
diurna,  occurring  in  the  blood  by  day  and  prevalent  in  West  Africa 
and  India ;  (3)  Filaria  perstans,  which  persists  in  the  blood  both  day  and 
night,  and  occurs  in  West  Africa  and  a  number  of  other  places." 

Rosenau1  describes  the  movements  of  filariae  in  the  body  of 
mosquitoes  fed  on  the  blood  of  filarial-infested  individuals  as 
follows : 

1  "Preventive  Medicine  and  Hygiene,"  New  York  and  London,  1918. 


14  MOSQUITO  ERADICATION 

"The  filarial  larvae  soon  escape  from  their  sheaths  in  the  thickened 
blood  within  the  stomach  of  the  mosquito.  They  pierce  the  stomach 
wall,  enter  the  thoracic  muscles  of  the  insect,  pass  through  a  metamor- 
phosis which  takes  from  16  to  20  days  (longer  or  shorter,  according  to 
atmospheric  temperature) ;  they  now  quit  the  thorax  and  a  few  find  their 
way  to  the  abdomen;  the  vast  majority,  however,  pass  forward  through 
the  prothorax  and  neck  and,  en  ering  the  head,  coil  themselves  up  close 
to  the  base  of  the  proboscis  and  beneath  the  pharynx  and  under  surface 
of  the  cephalic  ganglia." 

It  is  not  yet  definitely  known  whether  Culex  fatigans  is  the  only 
species  of  mosquito  which  transmits  filariasis;  for  this  reason, 
anti-mosquito  work  for  the  prevention  of  filariasis  should  be 
directed  against  all  the  mosquitoes  in  the  vicinity. 

Filariasis  occurs  throughout  the  tropics  and  sub-tropics 
generally,  and  the  total  morbidity  from  this  infection  undoubt- 
edly is  large.  In  the  United  States,  occasional  cases  are  reported 
in  the  Southeast,  the  endemic  area  reaching  as  far  north  as 
Charleston,  S.  C. 

ECONOMIC    SIGNIFICANCE    OF   YELLOW   FEVER,   DENGUE   AND 

FILARIASIS 

While  none  of  these  diseases  are  widely  prevalent  in  the 
United  States,  the  impairment  of  working  capacity  which  the 
last  two  entail — -which  probably  corresponds  in  a  large  measure 
with  that  caused  by  malaria — no  doubt  amounts  to  a  not  incon- 
siderable sum  annually. 

In  the  tropical  regions,  however,  where  these  diseases  are  much 
more  common,  it  is  clear  that  their  economic  significance  must  be 
very  large.  The  inefficiency  of  tropical  labor  has  been  noted  by 
virtually  all  persons  who  have  visited  those  parts,  and  it  is 
apparent  that  this  inefficiency  is  due  largely  to  malaria,  yellow 
fever,  dengue  and  filariasis — preventible,  mosquito-borne  diseases. 

THE  MOSQUITO  AS  AN  ANNOYANCE;  EFFECTS  UPON  HEALTH 

Little  need  be  said  as  to  this  phase  of  the  mosquito's  activities 
and  its  effects  upon  the  comfort  and  health  of  the  community, 
as  anyone  who  has  lived  in  vicinities  that  the  mosquito  frequents 
knows  how  much  discomfort  it  causes. 

Not  only  do  they  make  life  miserable  for  their  victims,  but, 
merely  as  an  annoyance  alone,  they  have  a  very  pernicious  effect 
upon  the  health.     The  illness  caused  by  loss  of  rest  and  sleep,  by 


THE  TOLL  OF  THE  MOSQUITO  15 

over-wrought  nerves  and  temper  and  bjr  poisonous  swellings 
that  sometimes  follow  the  bites  probably  would  reach  an  enor- 
mous figure,  were  such  cases  traced  down  and  recorded. 

Another  aspect  of  the  effect  upon  health  of  annoyance  by 
mosquitoes  is  the  possibility  that  they  may  have  some  connection 
with  other  diseases  than  the  four  hitherto  discussed.  There  are 
still  man}r  diseases  whose  etiology  is  as  yet  comparatively 
unknown,  and  the  possibility  is  by  no  means  remote  that  further 
investigation  may  show  that  the  mosquito  is  in  some  way  con- 
nected with  their  transmission. 

THE  MOSQUITO  AS  AN  ANNOYANCE;  ECONOMIC  SIGNIFICANCE 

But  the  economic  significance  of  the  mosquito  as  an  annoyance 
is  probably  even  more  apparent  than  its  significance  as  a  menace 
to  health.  The  mere  fact  that  mosquitoes  are  abundant  in  a 
region  holds  back  development  of  that  region  and  keeps  property 
values  down  to  a  very  low  figure. 

Speaking  of  the  economic  benefits  of  eradicating  mosquitoes 
along  the  New  Jersey  coast,  Headlee1  says: 

"Everywhere  (that)  the  drainage  has  been  completed  and  is  main- 
tained, the  thoughtful  residents  speak  of  the  great  relief  afforded.  As 
the  result  of  an  investigation  made  during  the  season  of  1912-13,  shore- 
line property  values  between  Jersey  City  and  Rumson  were  found  to 
have  increased  by  $5,600,000.  It  is  significant  of  the  influence  of 
mosquito  control  on  this  increase  to  note  that  while  the  increase  in  the 
factory  section  was  only  15  per  cent,  in  the  residential  portions  it 
ranged  from  25  to  300  per  cent.  This  tallies  well  with  the  observation 
that  parts  of  the  shore,  formerly  almost  uninhabitable  because  of  the 
mosquito  pest,  have  now  become  delightful  summer  resorts. 

"A  rather  unexpected,  but  very  natural,  benefit  has  appeared  as  a 
result  incidental  to  that  drainage  necessary  to  eliminate  salt  marsh 
mosquito-breeding.  An  estimate,  prepared  during  the  year  1912-13, 
showed  that  the  salt  marshes  which  had  been  drained  and  kept  drained 
3  years  or  more  were  producing  2.6  tons  of  hay  per  acre,  as  compared 
with  0.7  ton  produced  by  marshes  that  are  undrained  or  only  recently 
drained. 

INCREASING  PROPERTY  VALUES 

"It  is  well-nigh  impossible  to  prepare  reliable  estimates  of  the  value  of 
ridding  the  rest  of  the  salt  marsh  of  mosquito-breeding.     The  carrying 

1  "The  Mosquitoes  of  New  Jersey  and  Their  Control,''  New  Jersey  Agri- 
cultural Experiment  Stations,  Bull.  276,  1915. 


16  MOSQUITO  ERADICATION 

out  of  this  work  would  remove  the  greatest  bar  which  now  exists  to  the 
proper  urban  and  agricultural  development  of  South  Jersey.  The 
complete  occupation  of  the  shore  as  a  summer  resort  awaits  the  control 
of  the  mosquito.  Across  the  marsh  from  this  line  of  summer  resorts  is 
bound  to  appear  the  second  line  of  summer  residences.  Eventually, 
the  marsh  itself  will  be  filled  and  built  up.  The  agricultural  land  lying 
back  of  this  urban  development  will  be  called  upon  to  produce  truck  and 
fruit  to  supply  this  national  play-ground. 

"The  salt  marsh  mosquito  stands  in  the  way  of  this  tremendous 
development.  The  marshes  should  be  drained  and  the  mosquito 
destroyed." 

It  is  obvious  that  the  same  considerations  that  apply  to  mos- 
quito eradication  along  the  New  Jersey  coast  apply  in  larger  or 
lesser  degree  to  mosquito  eradication  in  similar  coast  areas.  It  is 
equally  obvious  that  they  also  apply  to  many  inland  areas. 
There  are  probably  millions  of  acres  in  the  United  States  where 
eradication  of  mosquitoes  as  a  mere  annoyance  alone  would 
greatly  increase,  if  not  double  or  treble,  property  values. 


CHAPTER  II 

SOME  DISEASE-BEARING  AMERICAN  MOSQUITOES 

THE  MOSQUITO  IN  GENERAL 

While  mosquitoes  have  a  world-wide  distribution,  they  differ 
very  materially  in  their  habitat,  their  appearance,  their  ability 
to  transmit  disease,  the  character  of  their  breeding-places  and 
the  mode  of  continuing  their  existence  from  one  generation  to 
another. 

From  the  point  of  view  of  habitat,  mosquitoes  may  conven- 
iently be  divided  into  three  general  classes:  The  domestic  mos- 
quito, which  breeds  largely  about  homes,  as  Aedes  calopus,  the 
yellow  fever  mosquito;  the  fresh-water  sylvan  mosquito,  which 
breeds  in  pools,  swamps,  streams,  ponds,  etc.,  as  the  Anopheles, 
the  malaria-carrying  mosquito;  and  the  salt-marsh  mosquito, 
which  breeds  almost  entirely  in  brackish  marshes  along  the  sea,  as 
Culex  sollicitans.  It  is  the  domestic  and  fresh-water  sylvan 
mosquitoes  which  constitute  the  menace  to  health. 

Of  its  own  volition,  the  mosquito  seldom  travels  far.  Experi- 
ments indicate  that,  as  a  rule,  the  inland  mosquito  does  not  fly 
more  than  half  a  mile  or  so  from  its  breeding-place  and  that  the 
average  flight  is  much  less  than  this  distance.  The}''  may,  how- 
ever, be  wafted  considerable  distances  by  the  wind,  and  this  fact 
should  be  borne  in  mind  in  planning  anti-mosquito  work;  the 
control  area  should  extend,  say,  a  mile  or  more  in  the  direction  of 
the  prevailing  wind,  while  the  other  side  may  be  reduced  in  width 
to  half  a  mile. 

LIFE  HISTORY  OF  THE  MOSQUITO 

Although  the  mosquito  is  a  winged  animal,  no  fewer  than 
three  of  the  four  stages  of  its  life  are  aquatic,  and  these  are  the 
first.  The  egg  is  laid  in  a  quiet  pool  or  other  suitable  breeding- 
place;  if  the  weather  is  warm,  in  a  couple  of  days  the  eggs  hatch 
out  into  larvae  (wiggletails  or  wrigglers) ;  in  4  or  5  days  more  the 
larvae  turn  into  pupae;  this  stage  lasts  2  or  3  days,  when  the 
adult   mosquito  emerges  from  the   pupal  shell.     Therefore,   if 

17 


18  MOSQUITO  ERADICATION 

conditions  are  favorable — that  is,  if  the  weather  is  warm,  the 
water  rich  in  food  and  other  factors  are  right — the  egg  may 
develop  into  an  adult  mosquito  in  8  to  10  days. 

The  length  of  life  of  the  adult  mosquito  varies  with  conditions. 
The  average  mosquito  probably  lives  several  months  under 
favorable  circumstances.  Guiteras  kept  one  alive  in  Havana  for 
154  days,  and  it  is  frequent  to  keep  them  alive  in  laboratories  for 
70  to  90  days.  Without  water,  however,  the  mosquito  will 
perish  in  4  or  5  days. 

The  character  of  the  breeding-place  varies  with  the  species  and 
with  conditions.  Thus,  the  domestic  mosquitoes  generally 
choose  water  impounded  in  artificial  containers  about  homes, 
such  as  barrels  and  cisterns,  tin  cans  and  bottles,  cesspools, 
shallow  wells,  etc.  The  fresh-water  sylvan  mosquitoes  may  be 
found  occasionally  in  this  class  of  breeding-place,  as  well  as  in 
forest  pools,  swamps,  ponds  and  streams,  their  usual  breeding- 
places.  The  character  of  breeding-place  of  any  given  group 
may  be  modified  by  conditions. 

VARIATIONS  IN  EGGS,  LARVAE  AND  PUPAE 

The  eggs,  too,  vary  materially  with  the  different  species.  The 
eggs  of  the  Culex  are  deposited  vertically  in  large,  brownish 
rafts;  those  of  the  Aedes  and  Anopheles,  on  the  other  hand,  are 
found  isolated,  one  by  one,  on  their  sides. 

The  habits  and  appearance  of  the  larvae  also  present  noticeable 
differences.  Although  all  larvae  are  aquatic  animals,  they  are, 
nevertheless,  nearly  all  air  breathers,  lying  just  under  the  sur- 
face of  the  water  and  connecting  with  the  air  supply  from  time 
to  time  by  means  of  a  breathing  siphon.  The  Anopheles  larvae 
recline  under  the  surface  of  the  water  in  a  horizontal  position, 
while  the  Culex,  Aedes  and  others,  on  the  contrary,  hang  with 
their  heads  down. 

The  pupae  of  all  species  do  not  eat,  having  no  mouth.  Like 
the  larvae,  however,  they  are  air  breathers,  breathing  through  a 
pair  of  trumpet-shaped  tubes  which  are  connected  with  the  thorax. 

Some  species  pass  the  winter  as  adults  hidden  in  natural 
shelters;  others  as  larvae;  and  still  others  as  eggs.  The  eggs 
of  some  mosquitoes  will  retain  their  vitality  after  having  been 
perfectly  dry  for  months;  exposure  to  water  for  a  few  hours  will 
result  in  the  hatching  of  larvae.  These  varied  methods  of 
survival  render  extinction  of  the  race  impossible. 


DISEASE-BEARING  AMERICAN  MOSQUITOES 
WHY  MOSQUITOES  BITE 


19 


Mosquitoes  bite  because  blood  is  believed  to  be  a  biological 
necessity  for  full  development  of  the  eggs.  As  this  necessity  is. 
only  a  feminine  one,  male  mosquitoes  are  vegetarians,  and  never 
bite.  They  may  be  distinguished  from  the  females  by  the  fact 
that  their  antennae  are  more  plumose — that  is,  more  heavily 
haired. 


'•"'W/iOft, 


Fig.  12. — Proboscis    of    mosquito  with  lancets    (stilette   bundle)    raised   out  of 
sheath.      (After  U.  S.  Public  Health  Service.) 

While  biting,  the  mosquito  pierces  the  skin  of  its  victim  by 
means  of  a  number  of  lancets  which  lie  in  the  beak.  As  they 
enter  the  skin,  the  beak  covering  bends  near  the  middle,  thus 


Fig.  13. — Proboscis  resolved  into  stilette  bundle.  (After  Daniels.)  A, 
labrum;  B,  two  mandibles;  C,  hypopharynx;  D,  two  maxillae;  E,  sheath  (labium). 
F,  distal  end  of  the  sheath. 

allowing  the  head  of  the  mosquito  to  get  up  close.     The  beak 
and  lancets  are  described  by  Headlee'  as  follows: 

"The  beak  covering,  which  is  the  only  member  of  the  mouth  append- 
ages seen  by  the  ordinary  observer,  corresponds  to  the  labium  or  lower 
lip  of  the  chewing  insect.     It  is  grooved  length- wise  along  its  upper 

1  "The  Mosquitoes  of  New  Jersey  and  Their  Control,"  New  Jersey  Agri- 
cultural Experiment  Stations,  Bull.  276,  1915-,—  r 


20 


MOSQUITO  ERADICATION 


surface  and  forms  a  trough  in  which  the  delicate  piercing  lancets  lie 
and  by  which  they  are  protected  from  harm. 

"The  lancets  consist  of  six  parts.  The  upper  is  a  compound  struc- 
ture, representing  the  labrum  or  upper  lip  and  the  epipharynx  of  the 
chewing  insect.  The  epipharynx  is  grooved  length-wise  of  its  lower 
surface  in  such  a  fashion  as  to  form  a  complete  tube  when  the  hypo- 
pharynx  is  laid  against  it  from  below.  The  hypopharynx  is  a  slender, 
flattened  piece  that  fits  closely  against  the  open  groove  of  the  epipharynx. 
Through  the  tube  thus  formed,  the  victim's  blood  is  drawn  into  the 
mosquito's  digestive  tract.  The  next  pair  of  lancets  are  slender  sharp- 
pointed  rods,  which  correspond  to  the  mandibles  or  primary  jaws  of 
chewing  insects.  The  next  pair  of  lancets,  which  correspond  to  the 
maxillae  or  secondary  jaws  of  chewing  insects,  are  slender  and  pointed, 
but  have  slightly  enlarged  barbed  ends. 


Fig.  14. — Mosquito  in  the  act  of  sucking  blood,  the  stilette  bundle  being 
free  from  the  sheath,  except  at  the  distal  end  of  the  sheath.  {After 
Bahr.) 

"Almost,  if  not  quite,  coincidently  with  the  moment  that  the  skin  is 
pierced,  a  small  amount  of  saliva  is  injected  through  the  epipharyngeal 
groove  into  the  wound,  and  suction  begins  very  soon  after  that.  The 
pumping  portion,  the  fore-intestine,  regularly  contracts  and  expands, 
drawing  the  blood  from  the  victim  into  the  mosquito's  body.  Unless 
disturbed,  the  creature  will  continue  to  feed  until  its  abdomen  is 
distended  almost  to  bursting." 


IDENTIFICATION  OF  MOSQUITOES 

Ability  promptly  to  identify  the  various  kinds  of  mosquitoes  is 
almost  an  absolute  necessity  for  the  director  of  an  anti-mosquito 
campaign.  Not  only  do  the  methods  to  be  used  for  their  eradica- 
tion depend  upon  the  species,  but  a  knowledge  of  the  particular 


DISEASE-BEARING  AMERICAN  MOSQUITOES  21 

species  prevalent  in  a  community  may  prevent  the  expenditure  of 
large  sums  in  measures  directed  against  species  which  are  not 
troublesome  there.  Furthermore,  if  occasional  mosquitoes  are 
noted  in  a  community  where  anti-mosquito  work  is  being  carried 
on,  knowledge  of  their  species  will  facilitate  determination 
whether  their  presence  is  due  to  failure  of  the  work  or  whether 
they  have  blown  in  from  the  salt  marshes  or  elsewhere.  Again, 
determination  of  the  species  causing  trouble  will  make  it  possible 
for  the  director  to  locate  their  breeding-places  through  knowledge 
of  the  habits  of  that  particular  species. 

This  necessary  acquaintance  with  the  more  common  species 
of  mosquitoes  can  be  obtained  only  by  familiarizing  oneself  with 
the  characteristic  outer  anatomy  of  the  adult  and  the  larvae,  so 
as  to  enable  one  readily  to  grasp  the  keys  used  in  classification. 
Mere  character  of  breeding-place  is  not  a  sufficient  basis  for 
identification. 

Adults  can  only  be  positively  identified  if  they  are  in  good 
shape — not  crushed  or  damaged  and  not  so  old  that  the  char- 
acteristic markings  have  worn  off.  The  most  favorable  age  for 
identification  is  1  or  2  days.  As  soon  as  caught,  the  specimen 
should  be  placed  in  a  jar  of  cyanide  or  other  toxic  gas  until  dead, 
after  which  it  may  be  pinned  through  the  thorax.  If  it  is  desired 
to  preserve  the  specimen,  it  should  be  carefully  placed  in  a  tight- 
closing  box  containing  naphthalene,  care  being  taken  to  attach 
an  identifying  paper  to  it. 

Larvae  and  pupae  may  be  placed  in  bottles  of  80  per  cent 
alcohol,  which  will  preserve  them  indefinitely,  so  that  they  will 
be  available  for  microscopical  examination  at  any  time.  They 
may,  if  desired,  for  permanent  reference,  be  mounted  on  slides 
with  Canada  balsam. 

ANATOMY  OF  THE  MOSQUITO 

"The  mosquito's  body,"  says  Headlee,1 

"like  that  of  most  other  insects,  is  made  up  of  three  distinct  regions — 
the  head,  thorax  and  abdomen.  The  head  is  a  globular  object  having 
(1)  a  pair  of  eyes,  one  on  each  side  of  the  head;  (2)  a  pair  of  more  (male) 
or  less  (female)  feathery  feelers  or  antennae;  (3)  a  pair  of  mouth  feelers 
or  palpi;  (4)  a  long,  prominent  beak.     The  thorax  is  long,  elliptical  and 

lUThe  Mosquitoes  of  New  Jersey  and  Their  Control,"  New  Jersey  Agri- 
cultural Experiment  Stations,  Bull.  276,  1916. 


22 


MOSQUITO  ERADICATION 


bears  three  pairs  of  legs  on  its  lower  surface  and  one  pair  of  more  or  less 
transparent  wings  on  its  upper  surface.  The  abdomen  is  long  and 
narrow  and  composed  of  many  plainly  defined  segments.     It  bears  no 


on      S1*1    tarsal    joint. 

Fig.   15. — Adult   mosquito,    (Aedes  sollicitans  Wlk.)  with  parts  named.      (After 
John  B.  Smith,  New  Jersey  Agricultural  Experiment  Stations.) 

appendages  other  than  certain  ones  connected  with  reproduction,  and 
apparently  they  are  not  necessary  in  elementary  classification. 

"Each  leg  consists  of  a  small  coxa,  a  long  femur,  an  equally  long  tibia 


DISEASE-BEAR  IXC  AMERICAN  MOSQUITOES  23 


ro/ary  mouth  brushes 


antenna/  tuff 

antenna 


Tfi/'nJ  s6cfomina/ 


^   fburtf,  a6<Jom/r>a/ 
&  SeSnier>f 

I 

9  rjffh  aSJo/Tf/oa/ 
7g  segment  -  -  ---. 


5/xth  aSc/om/na/ 
scqmenf- 


Seventh  abc/om/naf 
seamen / 

Eighth  ahc/om/rra/ 

Segnjcrrf 

Mnfh  aSdr/rj/ha/  _ 
orana/  -  =^ 
y sf3T^pt_  ~ 


snal  tuff  J 


thorsc/c 

,''  nairtuff.i 


,'  i  ana/  siphort 


--patch  of  sca/es 
con?6s  orpecfens 


-  Sp/ncs 
trachea/  ^//fs 


Fig.   16.— Mosquito    larva    with    pan-    Darned.     {After   John    B.    Smith      Y,  „• 
Jersey  Agricultural  Experiment  Stations.) 


24 


MOSQUITO  ERADICATION 


and  a  five-jointed  foot  or  tarsus.     The  last  tarsal  joint  is  tipped  with 
claws. 

"The  wings  have  scales,  generally  collected  along  the  veins.  The 
color  and  arrangement  of  the  scales  determine  the  uniformity  or  spotted 
appearance  of  the  wings." 

ANATOMY  OF  THE  LARVAE 

Headlee1  describes  the  larva  as  follows: 

"Like  the  adult,  the  wriggler  exhibits  the  three  divisions  of  the  body 
— head,  thorax  and  abdomen.     The  head  bears  a  pair  of  eyes,  a  pair  of 


antennal  case 
head 


—-trumjoets      or 
breatnino     lutes 

Inorax 


e~ue 


T 


mnnc  case 
ec  cases 


SUJimming 
baddies 


Fig.   17. — Mosquito    pupa    with    parts    named.      (After    John    B.    Smith,    New 
Jersey  Agricultural  Experiment  Stations.) 

antennae  and  rotary  mouth  brushes.  Each  antenna  exhibits  a  small 
bunch  of  hairs,  which  has  been  designated  as  the  antennal  tuft.  The 
thorax  has  various  tufts  of  bristles  scattered  over  it,  known  as  the 
thoracic  tufts.  The  abdomen  consists  of  eight  well-developed  segments, 
each  of  which  bears  some  tufts  of  bristles,  known  as  the  abdominal  hair 
tufts.  The  eighth  segment  has  grown  a  process  known  as  the  anal  tube 
or  siphon,  which  bears  a  double  row  of  spines  on  its  posterior  surface 
and  has  the  opening  of  the  breathing  system  at  its  tip.  In  nearly  all 
species,  this  tube  is  used  to  penetrate  the  water  surface  film  and  to  reach 
the  atmospheric  air.     The  ninth  segment  is  small,  bears  a  large  group 

1  "The  Mosquitoes  of  New  Jersey  and  Their  Control,"  New  Jersey  Agri- 
cultural Experiment  Stations,  Bull.  276,  1915. 


DISEASE-BEARING  AMERICAN  MOSQUITOES  25 

of  bristles,  the  anal  tuft  and  some  smaller  tufts.  The  anal  opening  is 
situated  at  the  outer  end  of  this  segment  and  the  tracheal  gills  extend 
outward  from  this  opening.  On  each  side  of  the  eighth  segment,  there  is 
a  little  patch  of  scales  that  are  much  used  in  classification." 

The  pupa  has  a  small  head  attached  to  a  very  large  thorax,  with 
the  abdomen  curled  around  under  the  latter.  The  breathing 
tubes  or  trumpets  outcrop  from  the  top  of  the  thorax,  while 
underneath  are  the  leg  and  wing  cases.  At  the  extreme  end  of  the 
curled  abdomen  are  the  swimming  paddles  by  which  this  strange- 
looking  creature  moves  about  from  place  to  place. 

THE  ANOPHELINAE 

Of  the  sub-family  Anophelinae,  no  fewer  than  6  genera,  com- 
prising at  least  25  different  species,  are  believed  to  transmit 
malaria.  Knab  gives  a  list  of  34  species  of  American  Anopheles, 
of  which  the  following  have  been  definitely  shown  to  serve  as 
hosts  for  the  malaria  parasite: 

A.  albimanus  A.  argyritarsis  A.  crucians 

A.  intermedium  A.  quadrimaculatus  A.  pseudomaculipes 

A.  tarsimaculata         A.  pseudopunctipennis      A.  occidentalis 

In  addition  to  these,  A.  punctipennis  has  been  shown  to  trans- 
mit malaria  under  laboratory  conditions,  but  whether  or  not  it  is 
an  important  vector  of  malaria  in  nature  is  not  yet  entirely 
established. 

The  Anopheles  of  sanitary  importance  in  the  United  States 
are:  A.  quadrimaculatus,  A.  crucians  and  A.  punctipennis  in  the 
East  and  South,  and  A.  occidentalis  along  the  Pacific  coast. 

Known  transmitters  of  malaria  elsewhere  include:  A.  sinensis 
in  India;  A.  costalis  in  Africa;  A.  claviger  in  Spain;  and  A. 
maculipennis,  which  is  believed  to  be  the  same  as  .4.  quadri- 
maculatus, in  other  parts  of  Europe. 

IDENTIFICATION   OF  THE  ANOPHELINAE 

Adult  Anopheline  mosquitoes  may  readily  be  distinguished 
from  all  other  genera  by  the  fact  that  the  wings  are  distinctly 
spotted.  Furthermore,  in  the  female,  the  palpi  (the  slender  rods 
found  on  either  side  of  the  beak  or  proboscis)  are  about  three- 
quarters  as  long  as  the  beak  itself,  while  the  same  organs  in  the 
females  of  other  species  (except  one,  which  has  a  curved  pro- 
boscis) are  seldom  one-quarter  the  length  of  the  beak. 


26 


MOSQ  UITO  ERA DICA  TION 


Adult  Anopheles  also  may  be  identified  by  their  peculiar  pos- 
ture while  resting  or  biting.     On  a  vertical  wall,  the  head,  thorax 


Fig.  18. — Head  of  Anophe- 
les, male.  (After  U.  S.  Pub- 
lic Health  Service.) 


Fig.  19. — Head  of  Anophe- 
les, female.  {After  U.  S. 
Public    Health   Service.) 


and  abdomen  form  one  straight  line,  pointing  downward  at  an 
angle  of  about  60  degrees  from  the  horizontal;  other  common 


1  z  3 

Fig.  20. — Resting  posture  of  mosquitoes.      (After  Sambon.)      1  and  2,  Anopheles; 

3,  Culex  pipiens. 

mosquitoes  sit  humped  up,  both  head  and  abdomen  being  lower 
than  the  thorax. 


Fig.  21. — Ova  of  Anopheles.  Fig.  22. —  Culex  egg  raft.    (After 

(After     U.     S.     Public    Health  U.  S.  Public  Health  Service.) 

Service.) 

Adult  Anopheles  also  may  be  distinguished  from  other  common 
mosquitoes  by  their  actions.  They  seldom  bite  in  the  day-time 
and  rarely  bite  a  person  moving  about;  the  Culex, 
on  the  other  hand,  bites  at  all  times.  The 
Anopheles  does  not  hum  so  loudly  as  other  com- 
mon mosquitoes. 


Fig.  23. — Greatly  enlarg- 
ed view  of  a  Culex  egg. 
(After  U.  S.  Public  Health 
Service.) 


Fig.  24/ — Greatly  enlarged 
view  of  an  Anopheles  maculi- 
pennis  egg.  (After  U.  S.  Pub- 
lic Health  Service.) 


DISEASE  BEARING  AM  ERIC  AX  MOSQUITOES 


27 


The  eggs  of  Anopheles  may  be  distinguished  from  those  of 
Culex  and  some  other  common  mosquitoes  by  the  fact  that  the 
former  are  laid  singly  and  are  supported  on  the  surface  of  the 
water  by  lateral  air-spaces,  while  the  latter  stand  vertically 
in  closely-packed  rafts. 


Fig.  25. — Larva  of  Anopheles.     (Afti  r 
U.  S.  Public  Health  Service.) 


Fig.     26. — Larva    of    Culex.      (After 
U.  S.  Public  Health  Service.) 


Anopheline  larvae  may  be  distinguished  from  the  larvae  of  all 
other  genera  by  the  fact  that  the  head  is  much  smaller  than  the 
thorax,  that  they  have  virtually  no  breathing  tube  and  that  they 


Fig.    27. — Pupa     of    Anopheles       Fig.  28. — Pupa  of  Culex  pipiens. 
punctipennis.       (After      Howard,       (After  Howard,  Dyar  and  Knob. 
Dyar  and  Knab.) 

lie  horizontally  under,  but  close  to  the  surface,  of  the  water, 
very  much  like  a  basking  pike.  All  other  common  American 
larvae,  on  the  other  hand,  have  the  head  larger  than  the  thorax, 
have  a  long  breathing  tube  and  hang  head  down  at  an  angle  of 
about  60  degrees  from  the  plane  of  the  water  surface.  Upon 
being  frightened,  Anopheles  larvae  usually  dart  about  parallel 
to  the  surface,  while  other  larvae  usually  dart  downward. 


28 


MOSQUITO  ERADICATION 


Anopheles  pupae  are  larger  in  the  antero-posterior  direction  and 
narrow  laterally,  while  Culex  pupae  are  short  and  broad  from  side 
to  side.  The  breathing  siphons  of  Anopheles  pupae  are  short 
and  trumpet-like,  while  those  of  Culex  larvae  are  long  and 
narrow. 

As  a  general  rule,  the  Anophelinae  prefer  natural  breeding 
places  to  artificial  ones  and  manifest  an  aversion  for  sewage- 
polluted  water  and  for  brackish  water,  although  they  are  occa- 
sionally found  in  such  waters.  Their  food,  in  the  larval  state, 
consists  mainly  of  algal  spores,  minute  insects  or  crustaceans, 
etc.  Some  authorities  state  that .  they  become  cannibalistic 
when  their  usual  food  becomes  scarce. 


A.   QUADRIMACULATUS  SAY 

Of  the  three  common  American  malaria-carrying  mosquitoes 
it  is  believed  that  A.  quadrimaculatus  Say  is  probably  responsible 
for  more  harm  than  either  of  the  other  two. 

A.  quadrimaculatus  may  be  distinguished  from  the  other  Ameri- 
can Anopheles  by  the  fact  that  it  is 
brownish  in  color  and  has  from  three 
to  five — but  generally  four — black- 
ish spots  on  the  second  and  fourth 
wing  veins,  whence  its  name  is 
derived.  These  spots  are  patches 
of  black  scales. 

A .  quadrimaculatus  passes  the  win- 
ter as  an  adult  female,  in  cellars, 
forests,  barns  and  other  sheltered 
places.  When  warm  weather  comes 
in  the  spring,  these  females  emerge 
from  their  hiding  places  and  deposit 
their  eggs.  From  50  to  75  are  laid 
at  a  time.  If  the  weather  is  favorable,  the  larvae  emerge  in  2 
or  3  days  and  begin  feeding.  In  from  4  to  6  days  of  warm 
weather — or  much  longer  in  cool — the  wrigglers  transform  into 
pupae;  2  or  3  days  more  and  the  adult  emerges.  Breeding 
appears  to  be  as  continuous  from  spring  to  autumn  as  tempera- 
ture and  other  conditions  will  allow. 

While  the  favorite  breeding-place  of  A.  quadrimaculatus  is 
grass-bordered  pools,  ponds,  pot-holes,  etc.,  it  has  been  reported 
to  breed  in  slowly  moving  streams.     It  will  also,  on  occasions, 


Fig.  29. — Anopheles  quadritnacu 
latus,  female. 


DISEASE-BEARING  AMERICAN  MOSQUITOES  29 

breed  in  artificial  containers.  A.  quadrimaculatus  has  also  been 
known  to  breed  in  salt  marshes  and  other  brackish  water  and, 
rarely,  in  sewage-polluted  water. 

A.  quadrimaculatus  enters  buildings  very  readily,  and  the 
slightest  opening  in  the  screening  will  be  taken  advantage  of. 
If  the  size  of  mesh  of  the  screen  is  less  than  No.  16  or  No.  14, 
painted,  small-sized  individuals  will  be  certain  to  get  in.  A. 
quadrimaculatus  enters  inhabited  buildings  at  night  and  makes 
its  exit  early  in  the  morning,  unless  so  gorged  with  blood  as  to  be 
unable  to  pass  through  the  screen.  In  this  case  it  may  be 
observed  resting  on  the  screen  next  clay. 

It  has  been  found,  by  means  of  the  recovery  of  stained  speci- 
mens previously  liberated,  that  A.  quadrimaculatus  sometimes  will 
travel  more  than  a  mile,  although  it  is  not  believed  that,  under 
average  conditions,  the  usual  flight  is  as  much  as  that.  It  is 
believed  that  A.  quadrimaculatus  could  become  of  sanitary 
importance  more  than  a  mile  from  its  breeding-place  only  if  the 
breeding-place  were  very  extensive  and  production  therein  very 
heavy. 

A.  CRUCIANS  WIED 

As  compared  with  the  other  Anopheles,  the  wing  of  the  crucians 
is  more  dusky  and  the  veins,  thereof,  more  prominently  marked. 
The  characteristic  marks  are  three  small,  blackish  spots- 
patches  of  black  scales — on  the  sixth  wing  vein,  thoracic  end, 
posterior  margin.  If  the  specimen  be  very  old,  the  end  spot  may 
be  indistinct. 

The  crucians  has  been  called  the  "clay-light  Anopheles" 
owing  to  its  habit — in  contrast  with  that  of  A.  quadrimaculatus 
and  A.  punctipennis — of  biting  during  the  day  and  early  evening. 
A.  crucians  enters  dwelling-places  fully  as  readily  as  does  A. 
quadrimaculatus;  it  may  also  frequent  privies  and  be  abundant 
underneath  houses.  Despite  these  circumstances,  A.  crucians  is 
believed  to  be  somewhat  less  efficient  as  a  vector  of  malaria 
than  A.  quadrimaculatus. 

A.  crucians  appears  to  be  able  to  travel  somewhat  further  than 
A.  quadrimaculatus,  recent  tests  indicating  that  this  species  can, 
on  occasions,  fly  as  far  as  7,000  feet. 

In  its  life-habits,  A.  crucians  is  similar  to  A.  quadrimaculatus. 
It  is  not  so  fastidious  as  to  character  of  breeding-place,  however, 
and  fairly  frequently  may  be  found   breeding  abundantly  in 


30 


MOSQUITO  ERADICATION 


brackish  waters  and  waters  contaminated  with  chemicals. 
Metz'  reports  that  he  has  found  crucians  breeding  freely  in  water 
so  impregnated  with  noxious  substances  from  the  drain  of  a 
chemical  factory  that  fish  were  unable  to  live  in  it. 

A.  crucians  apparently  is  not  quite  so  widely  distributed  as  is 
A.  quadrimaculatus,  its  habitat  evidently  being  somewhat  more 


Fig.  30. — Anopheles  crucians,  female. 

restricted.     Often,  where  it  is  found  at  all,  it  is  found  in  great 
abundance. 

A.  PUNCTIPENNIS  SAY 

This  species  may  be  distinguished  from  other  common  Ano- 
pheles by- the  fact  that  it  carries  a  large  square  or  oblong  white  or 
yellowish  patch  at  the  anterior  margin  of  the  wing,  near  the 
outer  end.  Sometimes,  there  is  a  blackish  patch  also  noticeable. 
The  white  patch  is  readily  visible  to  the  naked  eye,  and  is 
quite  perceptible,  even  when  the  insect  is  in  the  resting  position 
with  the  wings  crossed.  The  anterior  margin  of  the  wing  is 
dark,  while  the  balance  is  lightly  spotted  with  black,  with  an 
almost  invisible  white  spot  at  the  extreme  apex. 

The  life-habits  of  A.  punctipennis  are  similar  to  those  of  A. 

i"  Some  Aspects  of  Malaria  Control  Through  Mosquito  Eradication," 
U.  S.  Public  Health  Service,  1919. 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


31 


Fig.  31. — Larva    of    Anopheles    crucians.      {After    John    H.    Smith,    New    Jersey 

Agricultural  Experiment  Stations.) 
1,  larva;  2  head  from  above;  3,  antenna;  4,  palpus;  5,  mandible;  (>,  mentum; 
7,   anal  segments  from  side;  8,   anal  segments  from  above,  showing  spiracles; 
9,  one  of  the  scales.     All  are  greatly  enlarged. 


32 


MOSQUITO  ERADICATION 


quadrimaculatus,  except  that  punctipennis  appears  to  be  some- 
what less  fastidious  about  the  character  of  the  water  in  which  it 
breeds. 

A.  punctipennis  apparently  does  not  enter  houses  so  freely  as 
A.  quadrimaculatus  and  A.  crucians.  It  is  generally  a  porch- 
biter,  and  ordinarily  will  be  found  most  abundantly  in  the  early 
evening.     It  does  not  appear  to  fly  so  far  as  A.  quadrimaculatus. 

This  species  probably  is  the  most  common  of  the  North 
American  Anopheles. 

A.  OCCIDENTALIS,  D.  AND  K. 

This  mosquito,  the  common  malaria  carrier  of  the  Pacific 
coast,  has  been  considered  by  some  authors  to  be  identical  with 

A.  quadrimaculatus.  While  the  gen- 
eral appearance  is  quite  similar  to  that 
of  A.  quadrimaculatus,  there  are,  accord- 
ing to  Dyar,  well-defined  differences  in 
the  male  genitalia. 

It  appears  that  this  mosquito  is  of 
sanitary  importance  only  west  of  the 
Rockies. 

THE  CTJLICINAE 


Fig 


32. — Anopheles    puncti- 
pennis, female. 


The  sub-family,  Culicinae,  is  sub- 
divided into  two  genera — the  Culex 
and  the  Aedes.  Species  belonging  to 
both  of  these  genera  transmit  disease. 

Adults  of  this  sub-family  may  be  distinguished  from  adult 
A?wpheles  by  the  fact  that  the  palpi  are  long  in  the  male  and 
short  in  the  female,  while  the  Anopheles  of  both  sexes  have  long 
palpi.  Another  differentiation  is  the  fact  that  Culicines  have 
flat  abdominal  scales,  while  A7iopheles  do  not.  As  already 
intimated,  the  resting  position  of  the  Culicines  is  also  very 
different  from  that  of  the  Anopheles. 

The  difference  between  Anopheline  and  Culicine  larvae  has 
already  been  indicated. 

The  chief  differences  between  Culex  and  Aedes  may  be  summed 
up  as  follows: 

Adult  Culex  and  Aedes  are  best  distinguished  by  the  shape  of 
the  abdomen;  in  the  Culex,  the  abdomen  is  blunt,  with  short 
cerci;  in  the  Aedes,  it  is  tapered,  and  pointed,  with  distinct  cerci. 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


33 


Fig.  33. — Larva  of  Anopheles  punctipennis.     (After  John  B.  Smith,  New  Jersey 

Agricultural  Experiment  Station*.) 
1,  larva;  2,  head  above;  3,  palpus;  4,  mandible;  5,  antenna;  6,    mentum;  7, 
anal  segments  from  the  side;  8,   anal  segments  from  above,  showing  the  two 
spiracles;  9,  one  of  the  scales.     All  are  greatly  enlarged. 


34 


MOSQUITO  ERADICATION 


Eggs  of  the  Culex  are  laid  vertically  in  rafts  and  are  generally 
of  a  brownish  color,  while  eggs  of  the  Aedes  are  laid  in  clusters 
and  gradually  turn  black. 

The  larvae  of  Culex  are  easily  distinguished  from  those  of 
Aedes  by  the  air-tube;  in  the  Culex,  there  are  many  hairs  along 
its  posterior  aspect,  while  in  the  Aedes,  there  is  but  a  single  tuft 
near  the  end  of  the  pecten. 

The  pupae  manifest  few  differences. 


Anopheles  occidentalis,  male  and  female. 


AEDES  CALOPUS  MEIG  (STEGOMYIA  FASCIATUS  FAB.) 

Aedes  calopus,  the  yellow  fever  mosquito,  is  very  widely 
distributed,  it  being  found  from  38°  South  to  38°  North  latitude. 
As  a  rule,  Aedes  calopus  prefers  the  lowlands,  and  is  rarely  found 
in  the  higher  parts  of  the  South. 

The  yellow  fever  mosquito  is  essentially  a  domestic  mosquito, 
breeding  by  preference  in  standing  water  about  houses,  such  as 
that  in  cisterns,  barrels,  tin  cans,  bottles,  etc.  Rarely,  if  ever, 
is  this  mosquito  found  breeding  in  swamps,  pools  and  streams, 
the  favorite  haunts  of  the  malaria  mosquito. 

Although  Aedes  calopus  may,  as  an  adult,  survive  a  brief 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


35 


winter,  this  mosquito  generally  passes  the  winter  in  the  egg 
stage.  The  eggs,  which  are  shaped  something  like  a  cigar  and 
measure  about  half  a  millimeter  in  length,  are  laid  on  the  surface 
of  the  water  or  just  above  the  water-line.  They  can  withstand 
freezing  and  may  be  kept  dry  for  6  months  without  losing  their 
vitality.  They  do  not  form  rafts,  as  do  the  Culex,  but  lie  singly 
or  in  isolated  groups. 


Fig.  35. — Aedes  calopus,  female. 


Fig.  36. — Aedes  calopus,  male. 


In  about  36  to  48  hours,  if  the  weather  is  warm,  the  egg 
develops  into  the  larva,  which  also  is  very  resistant,  it  being 
apparently  able  to  stand  freezing  for  a  brief  period.  A  distin- 
guishing feature  of  this  larva  is  the  fact  that  it  has  a  black, 
barrel-shaped  breathing  siphon.  This  larva  is  easily  scared  and 
stays  at  the  bottom  of  the  water  a  good  share  of  the  time. 

If  the  weather  is  warm,  the  larva  turns  into  a  pupa  in  5  to 
8  days.  The  pupa  stays  near  the  surface  of  the  water  most  of  the 
time.     In  36  to  48  hours  the  adult  mosquito  emerges. 

Aedes  calopus  is  of  a  grayish  color  and  average  to  smallish 
size.  It  has  glistening  whitish  lyre-shaped  marks  on  the  back 
of  the  thorax,  with  silver-white  dots  on  the  sides.  There  are 
white  lines  at  each  tarsal  joint  and  on  the  palpi,  while  the 
scutellum  also  is  white.     Outside  of  the  markings,  the  female  is 


36  MOSQUITO  ERADICATION 

distinguished  from  Anopheles  mosquitoes  by  the  fact  that  the 
palpi  are  rudimentary. 

Being  smallish,  A.  calopus  can  pass  through  a  screen  composed 
of  16  strands  or  15  meshes  to  the  inch.  To  be  effectual,  there- 
fore, screens  should  have  more  than  15  meshes  to  the  inch. 

As  a  rule,  A.  calopus  does  not  fly  nearly  so  far  as  the  malaria- 
carrying  mosquitoes,  manifesting  an  apparent  desire  to  remain 
about  the  environment  that  gave  it  birth.  It  is  active  chiefly 
during  the  daj'-time,  resting  at  night,  unless  attracted  by  bright 
lights.  During  the  day-time  it  seeks  shade,  since  it  cannot 
survive  long  in  the  direct  sunlight.  It  is,  therefore,  chiefly 
dangerous  in  houses  or  in  brush,  etc. 

Rosenau1  says:  "It  ma}r  possibly  at  times  fry  across  the  street, 
but  it  is  evident  that  it  neither  flies  far  nor  is  it  ordinarily  trans- 
ported to  any  great  distance  on  railroad  cars,  although  it  may  be 
carried  over  seas  in  ships." 

CULEX  FATIGANS  WIED.   (C.   QUINQUEFASCIATUS    SAY) 

This  mosquito  is  believed  to  transmit  both  dengue  and  filariasis 
to  man.  It  is  very  widely  distributed  over  the  tropics  and  sub- 
tropics.  C.  fatigans  and  A.  calopus  are  two  of  the  commonest 
house  mosquitoes  in  the  Southern  States. 

While  these  two  species  are  constantly  associated  in  that 
section,  breeding  together  in  house-yards  in  the  same  water  and  in 
the  same  containers,  A.  calopus  has  been  exonerated  as  a  dissemi- 
nator of  dengue  and  filariasis,  while  C.  fatigans  has  been  found 
to  be  almost  wholly  responsible  for  the  spread  of  these  diseases. 

C.  fatigans,  like  A.  calopus,  is  essentially  a  domestic  mosquito, 
breeding  in  fresh  water  in  back-yards,  in  cisterns,  rain-water 
barrels,  tin  cans  and  other  miscellaneous  artificial  containers. 

C.  fatigans  is  a  smallish  to  medium-sized  mosquito,  ranging 
in  color  from  yellow  to  dark-brown,  with  light  bands  at  the  base 
of  each  segment.     Its  legs  and  proboscis  are  not  banded. 

Probably  the  quickest  way  of  distinguishing  C.  fatigans  from 
A.  calopus  is  by  the  fact  that  the  former  is  essentially  a  night- 
biter,  while  the  latter  is  a  day-biter.  This  is  very  perceptible, 
wherever  the  two  occur  together. 

The  larva  of  this  species  may  be  distinguished  from  that  of  A. 
calopus  by  the  fact  that  its  respiratory  siphon  is  brownish  and 
nearly  three  times  as  long  as  it  is  broad. 

1  "Preventive  Medicine  and  Hygiene,"  New  York  and  London,  1918. 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


37 


C.  fatigans  passes  the  winter  as  an  adult  female.  She  hides 
away  in  protected  places  and,  when  warm  weather  comes,  lays 
her  eggs  in  dark-brown  rafts  of  from  50  to  400  eggs.  In  about 
8  or  9  days,  if  the  weather  is  favorable,  the  adult  of  the  new 
brood  emerges.  Breeding  is  more  or  less  continuous  up  to  cold 
weather  in  the  autumn. 

C.  fatigans  ordinarily  does  not  fly  far.  However,  where  pro- 
duction is  heavy,  it  may  travel  2  or  3  miles. 


Fig.  37. — Adult  female  Culex  fatigans. 


SOME  COMMON  TROUBLESOME  MOSQUITOES 

In  the  next  few  pages,  several  of  the  more  common  annoying 
mosquitoes  prevalent  in  the  United  States  will  be  discussed 
briefly.  So  far  as  is  known,  none  of  these  transmit  disease, 
but  all  are  more  or  less  troublesome  in  mosquito  eradication 
work. 

For  the  purposes  of  this  discussion,  it  may  be  convenient, 
perhaps,  to  divide  these  mosquitoes  into  rough  groups  as  follows: 


38 


MOSQUITO  ERADICATION 


FlG.  38._ AdulfCulex  viviens.     {After  John  B.  Smith,  New  Jersey  Agricultural 

Experiment  Stations.) 
1,  adult  female;  2,  palpus  of  same;  3,  anterior;  4,  middle,  and  5,  posterior 
claws  of  male.     All  are  greatly  enlarged. 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


39 


house    mosquitoes,    fresh-water    sylvan    mosquitoes    and    salt- 
marsh  mosquitoes. 


Fig.  39. — Adult  of  Culex  restuans.     (After  John  B.  Smith,  New  Jersey  Agricul- 
tural Experiment  Stations.) 
1,  adult  female;  2,  appendage  to  tip  of  clasper;  3,  clasper  of  male  genitalia: 
4,  anterior  claws  of  female;  5,  mentum  of  larva;  G  and  7,  antennae  of  same.      All 
are  greatly  enlarged. 

HOUSE  GROUP 

Probably  one  of  the  most  annoying  mosquitoes  of  this  group 
is   Culex  pipiens,  Linn.,  a  close  relative  of  C.  fatiga?is.     This 


40 


MOSQUITO  ERADICATION 


species  is  very  widely  distributed  and  breeds  in  almost  any  kind 
of  water,  apparently  preferring  water  that  contains  sewage. 
It  will,  on  occasions,  breed  in  salt  water,  but  it  is  preferentially 
a  domestic  insect.  It  enters  inhabited  houses  freely  and  bites 
all  night.  The  adults  resemble  C.  fatigans  so  closely  that  it  is 
difficult  to   distinguish   them.     The   males   differ  most  in  the 


Fig.  40. — Adult  of  Aedes  vexans.      (After  John  B.  Smith,  New  Jersey  Agricul- 
tural Experiment  Stations.) 
1,  adult  female;  2,  anterior;  3,  middle,  and  4,  posterior,  claws  of  the  male. 
All  are  greatly  enlarged. 

genitalia;  the  pipiens  females  have  the  abdominal  banding 
continuous,  while  the  females  of  fatigans  generally  have  the 
pale  bands  interrupted  at  the  sides.  The  life  history  of  this 
mosquito  and  its  habits  are  very  similar  to  those  of  C.  fatigans. 
Culex  restuans,  Theob.,  is  quite  similar  to  C.  pipiens  in  appear- 
ance, being  distinguished  from  it  only  by  the  fact  that,  under  a 
magnifying  glass,  two  white  spots  are  often  noticeable  on  top  of 
the  thorax  and  in  front  of  the  other  white  marks.     C.  restuans 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


41 


Fig.  41. — Adult   of  Aedes  canadensis.     (After  John  B.  Smith,  New  Jersey  Agri- 
cultural Experiment  Stations.) 
1,  adult  female;  2,  ovipositor;  3,  palpus;  4,  margin  of  the  wing,  showing  the 
fringe  scales;  5,  part  of  vein,  showing  scales;  6,  anterior  claws  of  female;  7,  anterior; 
8,  middle,  and  9,  posterior  claws  of  male.      All  are  greatly  enlarged. 


42  MOSQUITO  ERADICATION 

differs  from  C.  pipiens  in  that  it  seems  to  prefer  clear,  clean  water, 
but  otherwise  its  habits,  etc.,  are  similar.  The  larva  differs 
from  that  of  C.  pipiens  in  that  the  antennal  tuft  is  less  than  half- 
way between  base  and  tip,  while  in  the  case  of  pipiens  larvae  it  is 
generally  more  than  this. 

FRESH -WATER  SYLVAN  GROUP 

Aedes  vexans,  Meig,  one  of  the  most  important  mosquitoes  of 
this  group,  is  a  smallish  insect  with  unspotted  wings  and  un- 
handed beak.  Its  tarsi  have  narrow  light  bands  at  the  base,  as 
do  the  abdominal  segments.  The  larva  has  a  spotted  head. 
Its  respiratory  siphon  is  about  three  times  as  long  as  it  is  broad. 
The  antennae  spring  from  the  sides  of  the  anterior  part  of  the 
head.  This  species  breeds  only  in  temporary  puddles,  eschewing 
permanent  water.  Some  eggs  hatch  after  every  rain;  frequently 
all  perish  by  drying  of  the  pool.  A.  vexans,  it  is  said,  will  fly  as 
far  as  5  miles.  This  mosquito  does  not  enter  houses,  but  prefers 
shady  places  such  as  under  trees  and  porches,  and  bites  day  and 
night. 

Aedes  canadensis,  Theob.,  has  a  black  proboscis,  a  brown, 
unmarked  thorax  and  unspotted  wings.  The  last  tarsal  segment 
is  white;  the  others  are  brown  with  white  bands  at  the  base  and 
tip.  A.  canadensis  is  found  probably  most  frequently  in  forest 
pools,  etc.,  and  is  not  supposed  to  travel  far.  The  larvae  are 
gray  with  dark  heads.  In  the  early  stages  the  larva  has  a  light 
transverse  band  about  its  neck.  The  scales  on  each  side  of  the 
eighth  segment  are  isolated  and  elongated.  The  life  history 
and  habits  of  this  insect,  generally  speaking,  are  similar  to  those 
of  A.  vexans. 

Mansonia  perturbans  Wlk.  (Coquilletidia  perturbans  Wlk.)  is  a 
large  brown  mosquito  with  a  very  irritating  bite.  Both  tarsal 
and  abdominal  segments  have  narrow  white  bands  at  the  base 
and  the  first  tarsal  joints  have  broad  bands  near  the  middle. 
The  proboscis  has  a  broad  white  band  in  the  middle  also.  This 
species  breeds  only  in  permanent  swamps.  The  larvae  and 
pupae  differ  from  all  others  in  that  they  remain  at  the  bottom  of 
the  pool,  drawing  their  oxygen  supply  from  certain  plant  roots, 
etc.  They  are  light  in  color  and  have  a  respiratory  siphon  shaped 
like  a  bottle.  The  larvae  of  this  species  hibernate,  attached  to 
roots,  etc.;  they  are  able  to  withstand  freezing.     According  to 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


i:; 


Headlee,1  there  is  only  one  brood  a  year,  egg-laying  starting  when 
many  of  the  previous  season's  larvae  are  still  small.  The  fact 
that  the  larvae  and  pupae  of  this  species  get  their  oxygen  from 
roots  under  the  water  renders  them  invincible  to  oil.  In  the  case 
of  this  species,  use  of  a  larvicide  is  indicated. 


Fig.  42. — Adult  of  Mansonia  perturbans.     (After  John  B.  Smith,   New  Jersey 

Agricultural  Experiment  Stations.) 

1,  adult  female;  2,  part  of  wing  vein,  showing  scales;  3,  anterior;  4,  middle, 
and  5,  posterior  claws  of  male  tarsi.     All  are  greatly  enlarged. 

Psorophora  ciliata,  Fabr.,  is  one  of  the  largest  mosquitoes  in  the 
United  States.  It  lays  its  eggs  in  depressions  likely  to  collect 
water  in  time  of  rains.  When  the  rains  come,  the  eggs  hatch  out. 
The  larvae  are  very  large,  and  feed  entirely  on  the  larvae  of 
smaller  species,  according  to  Dyar. 

1  "The  Mosquitoes  of  New  Jersey  and  Their  Control,"  New  Jersey  Agri- 
cultural Experiment  Stations,  Bull.  276,  1915. 


44 


MOSQUITO  ERADICATION 
SALT  MARSH  GROUP 


Aedes  solliciUuis,  Wlk.,  probably  is  one  of  the  most  troublesome 
of  the  salt  marsh  mosquitoes.  The  thorax  of  this  insect  is 
yellowish  on  top  and  the  sides  are  white;  broad  white  bands 


Fig.  43. — Adult    of    Psorophora    ciliata.      (After    John    B.    Smith,    New    Jersey 

Agricultural  Experiment  Stations.) 
1,  adult  female;  2,  palpus;  3,  anterior,  and  4,  posterior  claws  of  male.     All  are 
greatly  enlarged. 

encircle  the  proboscis  and  feet;  and  there  is  a  yellow  stripe  along 
the  bottom  and  a  white  stripe  along  the  top  of  the  abdominal 
segments.  A.  sollicitans  breeds  exclusively  in  the  salt  marshes, 
but  occasionally,  wind  conditions  being  suitable,  it  travels  great 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


45 


Fig.  44. — Adult  of  Aedes  sollicitans.     (After  John   B.  Smith,  New  Jersey  Agri- 
cultural Experiment  Stations.) 
1,  adult  female;  2,  palpus;  3,  anterior;  4,  median, .and  5,  posterior  claws  of  the 
male.     All  are  greatly  enlarged. 


46  MOSQUITO  ERADICATION 

distances — sometimes,  according  to  Headlee,1  as  much  as  40 
miles.  The  same  writer  says  of  it:  "It  is  the  greatest  single 
factor  now  operative  in  South  Jersey  in  depressing  real  estate 
values  and  preventing  the  proper  development  of  that  section 
of  the  State."  The  larvae,  of  a  grayish  color,  are  large  and  have 
a  respiratory  siphon  only  about  twice  as  long  as  broad.  The  head 
is  unmarked.  The  antennae,  sprouting  from  the  sides  of  the 
anterior  part  of  the  head,  are  not  pendant.     The  scales  form  a 


Fig.  45. — Adult  of   Aedes  taeniorhynchus.     (After  John  B.  Smith,  New  Jersey 

Agricultural  Experiment  Slatiojis.) 
1,   adult  female;  2,   anterior  claws;  3,  anterior;  4,   median,   and  5,   posterior 
claws  of  male.     All  greatly  enlarged. 

large  patch  on  each  side  of  the  eighth  segment.  The  race  sur- 
vives the  winter  in  egg  form  in  mud  or  damp  earth.  They  are 
able  to  withstand  several  months  of  dry  weather,  and  develop 
rapidly  as  soon  as  water  covers  them.  Headlee1  says  that  if  the 
water  lasts  only  long  enough  for  the  larvae  to  turn  into  pupae, 
the  pupae  will  get  enough  moisture  from  the  mud  to  enable  them 
to  live  long  enough  to  reach  the  adult  stage.  He  continues: 
"Apparently,  a  considerable  percentage  of  the  eggs  deposited 

1   'The  Mosquitoes  of  New  Jersey  and  Their  Control,"  New  Jersey  Agri- 
cultural Experiment  Stations,  Bull.  No.  276,  1915. 


DISEASE-BEARING  AMERICAN  MOSQUITOES 


47 


Fig.  46. — Adult  of  Acdes  cantator.      {After  John  B.  Smith,  New  Jersey   Agricul- 
tural Experiment  Stations.) 
1,  adult  female;  2,  palpus,  and  3,  anterior  claws  of  same;  4,  anterior;  .3,  median 
and  6,  posterior  claws  of  male.      All  are  greatly  enlarged. 


48 


MOSQUITO  ERADICATION 


during  any  one  season  fail  to  hatch  during  that  season  and  remain 
in  the  mud  until  the  following  one.  By  this  provision  of  nature, 
the  salt  marsh  is  always  stocked  with  eggs,  and  the  appearance 
of  the  brood  is  a  matter  of  water  covering,  high  temperature  and 
the  absence  of  fish." 

Aedes  taeniorhynchus  Wied.,  is  a  small,  black  insect,  with 
narrow  white  bands  around  the  proboscis,  the  bases  of  the 
abdominal  segments  and  the  bases  of  the  tarsal  joints,  except 
the  last,  which  is  wholly  white.     The  larva  may  be  distinguished 


Fig.  47. — Culex  salinarius,  female.   (After 
Howard.) 


Fig.  48. — Culex  salinarius,   male. 
Howard.) 


(After 


from  that  of  A.  sollicitans  by  the  fact  that  the  head  is  usually 
slightly  marked.  Like  A.  sollicitans,  and  A.  cantator,  this  mos- 
quito does  not  breed  in  permanent  marshes,  but  in  temporary 
pools  of  comparatively  fresh  water  along  the  coast;  usually,  A. 
taeniorhynchus  selects  less  salty  water  than  A.  sollicitans.  Other- 
wise, the  habits  of  A.  taeniorhynchus  are  similar  to  those  of 
sollicitans,  except  that  it  is  not  believed  to  travel  so  far. 

Aedes  cantator,  Coq.,  is  a  large,  brownish  mosquito  with  a  hairy 
thorax;  the  bases  of  both  the  tarsi  and  the  abdominal  segments 
have  a  faint,  white  band  about  them.  The  head  of  the  larva 
has  black  spots;  otherwise,  the  larva  is  similar  to  that  of  A. 
sollicitans.  A.  cantator  usually  selects  somewhat  fresher  water 
than  does  sollicitans,  but  not  quite  so  fresh  as  does  taeniorhynchus, 
its  choice  apparently  being  the  "back  pools,"  containing  a  large 
admixture  of  fresh  water. 


DISEASE-BEARING  AMERICAN  MOSQUITOES  49 

Culex  salinarius,  Coq.,  is  very  similar  to  C.  pipiens,  except 
that  it  is  somewhat  darker  and  thinner.  The  larva  is  distin- 
guishable from  that  of  C.  pipiens  by  the  fact  that  it  has  a  longer 
breathing  siphon,  which  tapers  uniformly  from  base  to  tip. 
This  species,  like  C.  pipiens,  winters  as  an  adult,  eggs  being  laid 
by  gravid  females  in  the  spring;  the  eggs  are  laid  in  rafts,  similar 
to  those  of  C.  pipiens.  This  species  occurs  over  the  whole 
Eastern  part  of  the  United  States,  breeding  in  permanent  water 
in  the  same  way  as  pipiens,  fatigans  (quinquefasciatus)  and 
restuans.  It  is,  perhaps,  most  common  in  fresh-water  swamps 
along  the  sea-coast  but  does  not  occur  there  exclusively. 


CHAPTER  III 
DEVELOPMENT  OF  CONTROL  MEASURES 

HISTORICAL  ASPECTS 

For  centuries,  the  origin  of  the  mosquito-borne  diseases  was 
shrouded  in  mystery.  At  times  they  were,  in  common  with 
other  diseases,  regarded  as  scourges  sent  by  God  to  punish  man. 
Finally,  during  the  Middle  Ages,  malaria  was  discovered  to  be  a 
definite  disease,  with  definite  symptoms  and  attributes.  As 
it  was  generally  prevalent  in  low,  swampy  areas,  where  humid 
mists  and  vapors  arose,  it  is  not  surprising  that  the  disease  was 
believed  to  be  caused  by  this  unhealthful  atmosphere.  From 
this  belief,  the  disease  derived  its  name,  mal  being  the  Italian 
word  for  "bad"  and  aria  being  the  equivalent  for  "air." 

Yellow  fever  was  for  many  years  considered  as  a  form  of 
malaria,  and  only  in  comparatively  recent  times  was  it  discovered 
to  be  a  distinct  disease. 

This  belief  as  to  the  origin  of  malaria  and  yellow  fever  continued 
until  well  into  the  nineteenth  century,  when  here  and  there  a 
physician  arose  who,  expressed  the  opinion  that  there  was  some 
connection  between  malaria  and  mosquitoes.  A  great  step 
forward  was  made  in  1880,  when  Alphonse  Laveran,  a  French 
army  surgeon,  announced  the  discovery  of  the  malaria  parasite 
in  the  blood  of  persons  suffering  from  malaria.  In  1884,  Laveran 
joined  the  protagonists  of  the  mosquito  theory,  but  was  unable 
to  offer  definite  proof  as  to  the  soundness  of  the  belief. 

Fifteen  years  later,  Sir  Ronald  Ross,  a  British  army  surgeon 
working  in  India,  discovered  the  parasites  described  by  Laveran 
in  the  stomach  walls  of  Anopheles  mosquitoes  which  had  been 
allowed  to  bite  persons  infected  with  malaria,  and  demonstrated 
that  they  underwent  certain  changes  while  in  the  body  of  the 
mosquito.  The  life-cycle  of  the  parasite  was  soon  afterward 
worked  out  and  the  whole  course  of  the  disease  laid  bare.  Final 
proof  of  the  correctness  of  the  theory  of  transmission  was  afforded 
in  1900,  when  Manson  and  Warren  were  bitten  in  London  by 
infected  mosquitoes  forwarded  from  Italy,  and  shortly  thereafter 

developed  malaria. 

50 


DEVELOPMENT  OF  CONTROL  MEASURES  51 

Flint  having  shown  in  1868  that  yellow  fever  was  distinct 
from  malaria  since  its  course  was  not  affected  by  use  of  quinine, 
Finlay,  in  1882,  announced  his  belief  that  the  disease  in  some  way 
was  transmitted  by  the  mosquito.  This  theory  was  fully  substan- 
tiated in  1900-1902  by  a  board  of  U.  S.  Army  medical  officers, 
who  proved  conclusively  that  Aedes  calopus  was  the  culprit. 
Although  the  infective  agent  was  not  found,  the  discovery  that 
yellow  fever,  like  malaria,  is  transmitted  by  the  mosquito  was 
sufficient  to  make  preventive  work  possible. 

BEGINNING  OF  MOSQUITO  CONTROL 

The  value  of  these  two  epoch-making  discoveries  was  at  once 
apparent.  Since  both  malaria  and  yellow  fever  were  transmitted 
in  nature  solely  by  mosquitoes,  the  only  thing  necessary  to  elimi- 
nate both  was  to  control  the  mosquito.  This  might  be  done 
either  by  destroying  the  mosquito  or  by  rendering  it  impossible 
for  it  to  get  access  to  malaria  or  yellow  fever  patients — in 
other  words,  by  screening — or  by  a  combination  of  both  methods. 

These  discoveries  meant,  to  put  it  in  another  way,  that  two  of 
the  chief  obstacles  to  man's  conquest  of  the  tropics  could  be 
brushed  aside.  They  meant  that  no  longer  could  these  scourges 
of  humanity  defy  all  sanitary  and  medical  measures.  They 
meant  that  great  engineering  works  like  railroads,  canals  and 
other  modern  necessities  of  trade  could  be  carried  through  to 
completion  anywhere  in  the  tropics. 

No  delay  took  place  in  applying  the  newly  gained  knowledge. 
The  first  great  demonstration  of  its  soundness  was  afforded  in 
1901,  when  Gorgas  freed  Havana,  Cuba,  from  yellow  fever  in 
3  months;  the  city  had  not  previously  been  without  yellow  fever 
for  150  years.  In  this  classic  campaign,  both  screening  and 
anti-mosquito  methods  were  utilized. 

SANITARY  CONQUEST  OF  THE  CANAL  ZONE 

But  it  was  in  the  sanitation  of  the  Panama  Canal  Zone  that 
Gorgas  achieved  his  greatest  triumph.  Malaria  and  yellow 
fever  had  disastrously  defeated  two  attempts  by  the  French  to 
complete  the  canal,  so  when  the  American  government  undertook 
the  great  task,  Gorgas  was  placed  in  charge  of  the  anti-mosquito 
work  in  the  whole  zone. 

Within  a  few  months,  yellow  fever  was  almost  eliminated. 
The  last  case  in  the  City  of  Panama  was  reported  in  1905,  while 


52 


MOSQ  1'ITO  ERA DICA  TION 


the  last  case  in  Colon  occurred  in  1906.     Thereafter,  yellow  fever 
was  unknown  in  the  Canal  Zone. 

Progress  rin  malaria  control  was  slower  but  no  less  sure.  The 
following  table1  will  show  in  an  abbreviated  form  the  very- 
material  reduction  in  the  malaria  morbidity  and  mortality  rate 
among  Canal  employes  during  the  latter  period  of  American 
construction.  The  rates  are  subject  to  the  qualification  that  they 
are  based  on  the  number  of  names  on  the  payroll  and  not  on  the 
true  average  number  of  persons  employed: 


Year 

Average 
number  of 

Death  from  malaria 

Hospital  cases  of 
malaria 

employes 

Number 

Rate  per 
10,000 

Number 

Rate  per 
100 

1906 

26,547 

233 

87.8 

21,739 

81.9 

1907 

39,343 

154 

39.1 

16,753 

42.6 

1908 

43,890 

73 

16.6 

12,372 

28.2 

1909 

47,167 

52 

11.0 

10.169 

21.6 

1910 

50,802 

50 

9.8 

9,487 

18.7 

1911 

4S,876 

47 

9.6 

8,987 

18.4 

1912 

50,893 

20 

3.9 

5,623 

11.0 

1913 

56 . 654 

21 

3.7 

4,284 

7.6 

1914 

44,329 

7 

1.6 

2,886 

6.5 

1915 

34 , 785 

9 

2.6 

1,570 

4.5 

1916 

33,176 

3 

0.9 

493 

1.5 

ANTI-MOSQUITO  WORK  ELSEWHERE 

The  work  at  Havana  and  Panama  gave  a  great  impetus  to 
anti-mosquito  campaigns  in  other  parts  of  the  world,  and  slowly, 
but  surely,  one  after  the  other  of  the  great  endemic  centers  of 
yellow  fever  were  cleaned  up.  Several  of  the  large  cities  of 
Brazil,  for  centuries  known  and  recognized  as  foci  of  the  dreaded 
"yellow  jack,"  were  successfully  attacked.  In  1905,  Belize, 
British  Honduras,  was  cleaned  up,  while  in  1906-07  a  successful 
campaign  was  conducted  in  the  British  West  Indies. 

In  1905,  an  epidemic  of  yellow  fever  broke  out  in  New  Orleans. 
Anti-mosquito  measures  were  at  once  employed  and  the  disease 
was  soon  stamped  out,  with  a  total  of  3,389  cases  and  443  deaths. 
This  compares  very  favorably  with  the  figures  of  the  great  epi- 

1  "A  Plea  and  A  Plan  for  the  Eradication  of  Malaria  Throughout  the 
Western  Hemisphere,"  Prudential  Insurance  Company  of  America,  1917. 


DEVELOPMENT  OF  CONTROL  MEASURES  53 

demic  of  1898  (before  the  manner  of  transmission  of  yellow  fever 
was  known)  in  which  there  were  13,817  cases  and  3,984  deaths. 
One  of  the  most  important  compaigns  for  the  suppression  of 
yellow  fever  in  recent  years  was  waged  in  Guatemala  in  1918 
by  the  International  Health  Board.  This  campaign,  directed 
by  Gorgas,  stamped  out  the  epidemic  in  a  few  weeks  and  elimi- 
nated one  of  the  last  important  endemic  foci  of  yellow  fever  in 
Central  America.  The  report  of  the  International  Health 
Board  says: 

"The  outcome  was  especially  gratifying  and  encouraging  in  that  it 
demonstrated  that  yellow  fever  could  be  controlled  with  the  personnel  and 
facilities  available  in  Central  American  countries  and  at  a  cost  well  within 
their  financial  ability." 

MALARIA  CONTROL  IN  UNITED  STATES 

Following  the  successful  campaign  for  the  elimination  of  yellow 
fever  along  the  Gulf  Coast  and  other  parts  of  the  South,  the 
attention  of  sanitarians  throughout  that  section  began  to  center  on 
control  of  malaria.  The  splendid  results  of  the  anti-malaria 
campaign  in  Panama  served  as  an  example  .of  what  might  be 
done,  but  the  people  were  slow  to  grasp  the  situation.  The  fact 
that  elimination  of  yellow  fever  in  the  South  had  been  brought 
about  more  bjr  isolating  patients  from  mosquitoes  than  by  eradi- 
cation of  mosquitoes  in  general  obscured  the  public  apprecia- 
tion of  the  possibilities  of  malaria  control.  The  bulk  of  the 
people  took  the  attitude  that  to  attempt  to  eliminate  mosquitoes 
and  malaria  would  be  a  waste  of  time. 

As  a  result  of  this  misconception  of  the  situation,  it  was  not 
until  several  years  had  elapsed  that  anything  very  definite  was 
accomplished.  However,  in  1914,  the  U.  S.  Public  Health 
Service  made  an  allotment  of  $17,000  for  anti-malaria  work, 
and,  within  the  next  few  years  several  valuable  and  far-reaching 
demonstrations  were  carried  out.  The'  results  of  a  few  of  these 
will  be  mentioned  here. 

INTERPRETING  RESULTS 

It  should  be  pointed  out  that,  in  the  following  tables,  the  per- 
centages of  infection,  as  found  by  blood  tests  prior  to  commence- 
ment of  work,  should  not  be  considered  as  representing  the  total 
of  infections  during  the  previous  malaria  season.  These  blood 
test  percentages  should  be  regarded  as  merely  that  fraction  of  the 


54  MOSQUITO  ERADICATION 

total  number  of  persons  infected  who  had  not  been  able,  either 
by  natural  resistance  or  by  the  use  of  quinine,  to  banish  the  Plas- 
modia from  their  systems.  Thus  at  Roanoke  Rapids,  as  will 
be  seen  later,  the  blood  tests  in  the  fall  showed  13.75  per  cent  of 
the  total  population  infected  with  plasmodia;  during  the  mosquito 
season,  however,  about  75  per  cent  of  the  total  population  was 
infected,  according  to  the  health  officer. 

It  should  also  be  borne  in  mind,  in  interpreting  the  percentages 
of  reduction  of  persons  reporting  infection  or  illness  (history  index) 
and  of  physicians'  calls,  etc.,  that  what  may  seem  like  a  heavy 
remaining  infection,  despite  a  considerable  reduction  due  to 
control  work,  may  be  only  recurrences  of  former  infection.  As 
intimated  in  Chapter  I,  chronic  cases  may  regain  their  acuteness 
when  the  bodily  resistance  becomes  disturbed  or  weakened, 
without  there  being  a  new  infection  at  all.  Thus,  the  work  may 
be  very  effective  and,  indeed,  prevent  any  new  infection  at  all, 
despite  the  fact  that  the  history  index  and  the  records  of  physi- 
cians' calls  may  still  show  quite  a  percentage  of  cases.  These 
chronic  cases  however,  show  a  marked  reduction  year  by  year 
when  the  work  is  kept  up. 

Owing  to  the  difficulty  of  ascertaining  in  cases  of  protracted 
illness  whether  the  patient  is  suffering  from  one  chronic  infection 
or  repeated  new  ones,  it  has  been  found  generally  that  compari- 
sons of  physicians'  calls  gives  a  better  idea  of  the  effectiveness  of 
the  campaign  than  comparisons  of  cases.  Just  what  the  relation 
of  calls  to  cases  may  normally  be  is  not  definitely  known.  It  is 
believed,  however,  that  in  general,  especially  where  the  sickness 
is  wide-spread,  physicians  do  not  average  more  than  two  calls  to 
a  case,  and  frequently  not  that. 
EARLY  UNITED   STATES  MALARIA  CONTROL  DEMONSTRATION 

Roanoke  Rapids,  N.  C,  is  a  cotton-mill  town  in  the  northern 
part  of  the  state,  having  a  population,  including  two  nearby 
mill  villages,  of  approximately  4,100  in  1913.  During  the 
summers  of  1910,  1911,  1912  and  1913,  according  to  the  health 
officer,  75  per  cent  of  the  people  of  Roanoke  Rapids  suffered 
from  malaria.  During  the  same  periods,  this  physician's  visits 
on  account  of  malaria  alone  averaged  about  50  a  day. 

Anti-mosquito  work  was  begun  under  auspices  of  the  U.  S. 
Public  Health  Service  in  January,  1914  and  continued  until 
the  end  of  the  season  of  1916.     The  following  table1  shows  the 

1  "  Demonstrations  of  Malaria  Control,"  U.  S.  Public  Health  Service,  1918. 


DEVELOPMENT  OF  COXTROL  ME  AS  CUES 


.->;> 


reduction  in  prevalence  of  malaria  as  revealed  by  blood  examina- 
tions, by  house-to-house  inquiry  and  by  census  of  the  sick, 
together  with  costs  of  the  work  year  by  year: 


1913 

1914 

1915 

1916 

Blood  tests,  per  cent  infected. 

13.75 

4.48 

3.51 

1.58 

Per  cent  reporting  fevers 

46.60 

33.00 

19.10 

16.70 

Persons  sick  in  bed,  Oct.  1 . .  . 

200 . 00 

1.00 

none 

none 

Health  officer's  daily  calls. .  . . 

50.00 

1.00 

0.33 

Cost  of  anti-mosquito  work.. . 



$3683.41 

$1233.20 

$1237.31 

Per  capita  cost  of  work 

0.80 

0.27 

0.27 

This  big  reduction  in  the  incidence  of  malaria  at  comparatively 
small  cost  aroused  great  enthusiasm  among  the  mill  owners, 
who  previously  had  suffered  serious  losses  owing  to  illness  of  some 
emploj^es  and  seasonal  departure  of  others  to  escape  malaria. 
The  following  is  taken  from  a  letter  written  by  the  treasurer 
of  the  Roanoke  Mills  Co.  to  Surgeon  R.  H.  von  Ezdorf:1 

"I  will  frankly  admit  that  I  could  not  realize  what  a  great  change 
could  be  brought  about  by  systematic  work  and  with  comparatively 
little  expense.  The  money  spent  in  anti-malarial  work  here  has  paid 
the  quickest  and  most  enormous  dividends  I  have  ever  seen  from  any 
investment,  and,  after  having  had  our  experience,  I  would,  if  necessary, 
do  the  work  over  again  if  I  knew  it  would  cost  ten  times  the  amount." 


DEMONSTRATION  AT  ELECTRIC  MILLS,  MISS. 

Electric  Mills,  Miss.,  is  a  lumber  town  in  northern  Mississippi, 
situated  in  a  flat,  rolling  country  with  numerous  surrounding 
water-courses.  The  mill  physician  said  that  during  September, 
1912,  95  per  cent  of  all  sickness  for  the  month  was  due  to  malaria 
and  that  only  two  white  families  in  town  had  not  been  afflicted 
with  it. 

Anti-mosquito  work  was  commenced  in  May,  1914,  by  and 
under  the  direction  of  Assistant  Surgeon  General  H.  R.  Carter 
of  the  U.  S.  Public  Health  Service.  The  following  table2  shows 
the  reduction  in  incidence  of  malaria  year  by  year,  and  the  cost 
thereof : 

1  "Demonstrations  of  Malaria  Control,"  U.  S.  Public  Health  Service,  191S. 


56 


MOSQUITO  ERADICATION 


1913 


1914 


1915 


1916 


Blood  tests,  per  cent  infected i     11 .761        3.79 

Mill  physician's  cases  yearly 144 .00        85 .  00 

Cost  of  anti-mosquito  work $725 .  50 

Per  capita  cost  of  work 1.21 


70.00 

$143.80 

0.24 


1.46 


AThis  blood  test  was  made  in  May,  1914,  but,  as  it  represents  the  situation 
before  control  work  started,  it  is  placed  under  1913. 

CO-OPERATIVE  DEMONSTRATION  AT  CROSSETT,  ARK. 

Crossett,  Ark.,  is  a  lumber  town  in  the  low  part  of  the  state. 
The  population  in  1916  was  estimated  at  2,029.  Work  was 
started  there  in  May,  1916,  under  a  co-operative  arrangement 
between  the  U.  S.  Public  Health  Service  and  the  International 
Health  Board.  The  reduction  in  the  incidence  of  malaria  and 
costs  for  the  years   1916-17  are  given   in  the  tollowing  table1: 


1915 


1916 


1917 


Blood  tests,  per  cent  infected 9.43  2.61 

Physicians'  visits  for  malaria 2 ,  502 .  00        741 .  00 

Cost  of  anti-mosquito  work ! $2 ,  506 .  40 

Per  capita  cost  of  work 1 .  24 


277.00 

,275.45 

0.63 


In  1917-18  further  demonstrations  were  made  in  Hamburg, 
Lake  Village,  Dermott,  Monticello  and  Bauxite,  Ark.  The 
reduction  of  calls  for  malaria  ranged  from  78.4  to  97.4  per  cent 
and  the  per  capita  costs  from  $0.46  to  $1.45. 

WORK  OF  ST.  LOUIS   &  SOUTHWESTERN  RAILROAD 

During  1916,  steps  were  taken  by  the  St.  Louis  &  Southwestern 
Railroad  to  undertake  measures  for  the  control  of  what  had  been 
observed  to  be  an  undue  incidence  of  malaria  among  its  employes. 
It  had  been  found  that  during  the  preceding  4  years,  about  25 
per  cent  of  all  admissions  to  the  hospital  at  Texarkana  had  been 
for  malaria,  an  annual  average  of  640  cases  having  been  treated 
for  about  5  days  each;  this  was  equivalent  to  about  4  per  cent  of 

1(<  Malaria  Control:  A  Report  of  Demonstration  Studies,"and  "Malaria 
Control;  Results  Obtained  by  a  Local  Community,"  U.  S.  Public  Health 
Service,  1917  and  1918. 


DEVELOPMENT  OF  CONTROL  MEASURES 


oi 


15,000  employes,  and  did  not  include  such  cases  as  were  treated 
by  local  physicians.  An  appropriation  of  about  $3,000  was 
made  for  the  purpose  of  initiating  anti-mosquito  measures, 
which  were  begun,  in  co-operation  with  the  U.  S.  Public  Health 
Service,  at  Tyler,  Lufkin  and  Keltys,  Tex.,  early  in  1917. 


Calls  for 

Malaria 

before  and  after  Contro 

Work  Started 

tfeor  in  which 

work  began 

13  printed  in 

/TAUCS 

0 

c 

0 

rvj 

0 

0 

n 

0 

I. 

§ 

§ 

1 

0 

c 

01 

0 

■■■. 

I 

1 

0 

1 

1 

5 

1 

| 

§    1    § 

$  iS  5: 

$  5    s> 

S    5>     s 

HAMBURG 

1916   ^■■■■■■■■■■■1 

■■■ 

— ,^ 

_ 

^__ 

/S/7  ■■■ 

1918  f 

LAKE    VILLA 

GE 

I9I7B1 

1918  W 

DERM  OT  T 

1917  tallllllllM 

/3/SPI 

MONT/CELLO 

r^Y^Y^T^Y^T^Y^^^^^^^^^^ 

1917  ^■IIIIIMMi 

/9i8m 

BA 

UX/TE 

HIM    _               J 

1917  ■■■■■■■! 

!9I8  ■■ 

0 

S 

1 

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1 
9 

6 

6 

-4 

15 

1 

^- 

9 

1 

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\ 

5 

§ 

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I 

■ 

-• 

s 

5 

S    1   § 

1  fc  s 

Q    c    g 

<s  <i   5 

^  ?>   £ 

<\j    Rj     <\j 

Fig.  49. — Results  of  mosquito  eradication  campaigns  at  Hamburg,  Lake  Village, 
Dermott,  Monticello  and  Bauxite,  Ark. 

The  following  table  shows  the  cases  of  malaria  admitted  to  the 
hospital  at  Texarkana  from  places  where  anti-mosquito  work 
was  carried  on  in  1916  and  1917  respectively: 


in  lc. 


1917 


Number  of  cases  admitted . 
Per  cent  of  decrease 


13 
59.4 


58  MOSQUITO  ERADICATION 

At  Tyler,  the  sale  of  physicians'  prescriptions  containing 
quinine  decreased  about  49  per  cent  in  1917,  as  compared  with 
1916. 

Results  obtained  at  Keltys,  where  malaria  formerly  had  been 
severe,  are  particularly  interesting.  The  manager  of  the  lumber 
mill  there  stated  in  1917  that,  had  malaria  prevailed  to  the  same 
degree  as  in  1916,  the  mill  would  have  been  closed  about  one- 
half  the  time.  The  net  loss  of  this  to  the  railroad  in  freight 
charges  alone  would  have  been  about  $30,000. l 

The  railroad  prompted  by  the  success  of  this  demonstration, 
considerably  expanded  its  work  against  mosquitoes  in  later 
years.  In  1920,  its  appropriation  for  this  work  amounted  to 
$41,150,  while  $15,000  additional  was  appropriated  by  different 
towns  along  the  line  under  a  co-operative  plan  for  mutual  malaria 
protection.2 

In  1920,  the  Central  of  Georgia  Railroad  appropriated  $14,000 
for  similar  work.  Several  other  interstate  railroads  are  also 
known  to  be  contemplating  making  appropriations  for  this 
work. 

UNITED  STATES  ANTI-MOSQUITO  WORK  DURING  WORLD  WAR 

In  view  of  the  heavy  morbidity  records  of  army  camps  in  the 
South  during  the  Civil  and  Spanish-American  wars,  it  was 
deemed  essential,  when  the  United  States  entered  the  World 
War  in  1917,  to  institute,  among  other  health  measures,  anti- 
mosquito  campaigns  in  the  areas  surrounding  Southern  military 
cantonments,  naval  reservations,  aviation  camps,  munition 
plants,  ship-yards  and  important  war-industrial  projects. 

It  was  realized  that  the  introduction  of  thousands  of  recruits 
and  of  large  forces  of  labor  from  areas  in  which  the  mosquito- 
borne  diseases  were  prevalent  would  produce  new  conditions  at 
and  about  towns  in  which  this  war  work  was  carried  on  that 
would  make  extra  precautionary  measures  essential.  In  order 
therefore,  to  provide  complete  protection,  it  was  decided  that 
anti-mosquito  campaigns  should  be  carried  on,  not  only  within 
the  cantonments,  ship-yards  and  war-industrial  areas,  but  also 
within  an  area  a  mile  wide  surrounding  such  war  establishments 
and  towns  near  or  in  which  they  were  situated. 

In  order  to  prevent  conflict  of  jurisdiction,  army  and  navy 

1  Annual  Report,  U.  S.  Public  Health  Service,  1918,  page  23. 

2  Annual  Report,  U.  S.  Public  Health  Service,  1920,  page  20. 


DEVELOPMENT  OF  CONTROL  MEASURES  59 

organizations  were  placed  in  charge  of  the  anti-mosquito  work 
within  the  war-project  reservations,  while  the  U.  S.  Public 
Health  Service  was  placed  in  charge  of  the  work  in  the  mile  wide 
territories  outside  of  and  surrounding  the  war  project  areas  and 
towns  adjacent  thereto. 

"It  was  not  known  in  advance,"  says  LePrince,1  "how  many  camps 
were  to  be  established,  when  or  where  they  were  to  be  located,  nor  what 
force  of  trained  engineers,  foremen  and  labor  would  be  needed;  but  it 
was  very  apparent  that  as  soon  as  each  camp-site  was  approved,  mos- 
quito control  measures  and  drainage  operations  should  be  expedited  in 
order  to  head  off  malaria  transmission  in  that  locality." 

The  result  of  the  work  was  that  the  sick-rate  from  mosquito-borne 
diseases  was  cut  down  to  virtually  nothing;  what  little  malaria  there  was 
consisted  almost  entirely  of  men  already  infected  before  reaching  the 
war-project  areas.  As  LePrince1  says,  "The  malaria  sick-rate  among 
enlisted  men  in  camp  has  been  very  much  lower  than  it  would  have  been 
had  the}r  stayed  at  home." 

FORTY-THREE  WAR-PROJECT  AREAS  PROTECTED 

This  great  anti-mosquito  project  was  carried  out  by  the  Public 
Health  Service  in  43  war-project  areas  scattered  over  15  states. 
The  area  protected  covered  1,200  square  miles;  the  population 
protected  included  a  civil  population  of  about  1,750,000  and  an 
average,  constantly-changing  military  and  naval  population 
of  800,000.  The  total  cost  of  the  anti-mosquito  work  averaged 
about  $1.80  per  acre  of  territory  protected  or  about  54  cents  for 
each  person  protected.  About  one-third  of  this  cost  was  met 
by  the  communities  involved. 

This  work  was  carried  on  at  the  following  places  in  the  South ; 

Alabama — Sheffield,  Tuscumbia,  Florence,  Anniston,  Montgomery. 
Arkansas — Little  Rock,  Lonoke. 
Florida — Jacksonville. 

Georgia — Macon,  Augusta,  Atlanta,  Columbus,  Americus. 
Kentucky — Louisville. 
Louisiana — Lake  Charles,  Alexandria. 

Mississippi — Biloxi,  Gulfport,  Pass  Christian,  West  Point,  Hattiesburg, 
Jackson. 

North  Carolina — Charlotte,  Raleigh,  Fayetteville,  Wilmington. 
South  Carolina — Columbia,  Greenville,  Spartanville,  Charleston. 
Tennessee — Memphis,  Millington,  Nashville,  Chattanooga. 
Texas — Dallas,  Fort  Worth,  Houston,  San  Antonio,  Orange. 
Virginia — Newport  News,  Petersburg,  Alexandria,  Portsmouth,  Quantico. 

•"Mosquito  Control  About  Cantonments  and  Ship-yards,"  U.  S.  Public 
Health  Service.  1919. 


60  MOSQUITO  ERADICATION 

POST-WAR  MOSQUITO  CONTROL 

The  brilliant  results  obtained  through  the  war  anti-mosquito 
work  of  the  U.  S.  Public  Health  Service  acted  as  a  great  stimulus 
to  further  efforts  in  this  direction  throughout  the  South.  Many 
of  the  towns  in  which  these  campaigns  were  conducted  during 
the  war  have  continued  the  work  ever  since. 

In  addition  to  these  and  other  towns,  which  conducted  their 
own  work  independently,  and  to  the  work  conducted  in  many 
towns  along  its  lines  by  the  St.  Louis  &  Southwestern  Railroad, 
more  than  40  towns  and  cities  throughout  the  South  initiated 
campaigns  in  1920  under  a  co-operative  plan  which  included  the 
State  Health  Departments,  the  International  Health  Board 
and  the  Public  Health  Service.  This  number  was  considerably 
increased  in  1921. 

Approximately  $280,000  was  expended  by  various  communities 
in  anti-mosquito  work  between  July  1,  1919,  and  June  30,  1920, 
according  to  reports  received  by  the  Public  Health  Service. 
These  reports  were  by  no  means  complete,  as  they  included  only 
those  communities  which  were  known  to  have  been  directly 
influenced  in  carrying  on  anti-mosquito  work  by  the  activities 
of  the  Service.  They  did  not  include  many  communities 
indirectly  persuaded  of  the  importance  of  the  work  through 
Service  demonstrations  nor  thousands  of  individuals  awakened  to 
the  value  of  protecting  themselves  from  mosquitoes  and  informed 
as  to  practical  methods  of  doing  so. 

THE  SITUATION  TODAY 

The  following  statement,  bearing  upon  the  value  of  anti- 
malaria  campaigns,  their  progress  and  the  recent  notable  change 
in  public  appreciation  thereof,  by  LePrince,1  who  has  had  direct 
supervision  of  such  activities  of  the  Public  Health  Service  since 
they  were  first  undertaken,  is  believed  to  be  an  accurate  review 
of  prevailing  sentiment  along  anti-mosquito  lines  in  the  United 
States  today: 

"Malaria  fevers  cause  an  annual  loss  of  efficiency  each  year  in  our 
country  that  is  appalling,  and  the  communities  that  suffer  lack  interest 
in  public  welfare.  In  many  villages  and  towns,  from  10  to  40  per  cent 
of  the  inhabitants  are  infected.  Where  such  conditions  obtain,  the 
community  cannot  and  does  not  progress  or  develop  normally. 

1  Annual  Report,  U.  S.  Public  Health  Service,  1920. 


DEVELOPMENT  OF  CONTROL  MEASURES  61 

"It  has  been  definitely  demonstrated  that  many  of  the  localities  so 
affected  can  eliminate  malaria  at  a  reasonable  cost  and  that  the  best 
way  of  inducing  the  public  to  do  so  is  to  carry  on  carefully  planned 
demonstration  campaigns  in  badly  infected  areas.  The  result  of  such 
campaigns  means  a  much  larger  annual  income  for  the  community, 
the  county,  the  state  and  the  Federal  Government.  Preventive  malaria 
work  is  in  reality  a  sound  business  investment.  Up  to  1913,  no  county 
or  state  made  any  appropriation  for  malaria-control  operations,  although 
the  value  of  such  work  was  proved  12  years  previously. 

CHANGE  IN  PUBLIC  VIEW-POINT 

"As  a  result  of  the  malaria  investigation  work  directed  by  the  U.  S. 
Public  Health  Service,  the  public  view-point  has  changed — villages, 
towns,  county  and  state  officials,  as  well  as  business  corporations  and 
railroads,  now  realize  the  extent  of  the  large  preventable  financial  loss 
they  incur  each  year,  and  steps  are  being  taken  by  them  to  prevent  it. 
In  1913,  one  single  demonstration  control  campaign  was  started. 
In  1914,  congressional  appropriations  permitted  an  allotment  of  $17,000 
by  the  Service  for  malaria-control  investigations.  The  people  have  been 
watching  the  campaigns  undertaken  and,  throughout  the  country, 
they  are  becoming  more  and  more  interested  in  having  their  own  com- 
munity and  state  undertake  this  work. 

"During  the  past  fiscal  year,  64  separate  communities  carried  out 
malaria-control  campaigns,  and  appropriated  $280,000  therefor.  Nearly 
all  of  these  places  will  continue  to  maintain  this  freedom  from  malaria 
by  proper  safe-guards,  because  they  find  it  a  good  investment  to  do  so. 
This  calendar  year,  101  places  are  doing  work  under  the  supervision  of 
the  Public  Health  Sendee,  and  have  already  appropriated  about 
$350,000  therefor.  Several  states,  for  the  first  time  in  history,  have 
made  annual  appropriations  for  malaria  control  and  other  states  con- 
template doing  so.  Two  railroads  are  spending  for  malaria  elimination 
this  year  more  than  four  times  the  Federal  allotment  referred  to — their 
past  experience  shows  that  it  pays  to  do  so. 

GROWTH  OF  APPRECIATION 

"Industries  in  infested  areas  report  from  10  to  40  per  cent  increased 
output  after  control  measures  are  in  operation.  Chambers  of  commerce 
report  new  industries  establishing  branches  in  towns  where  the  elimina- 
tion of  malaria  has  rendered  local  labor  more  efficient,  and  factory 
managers  report  that,  since  malaria-control  measures  were  carried  out, 
there  is  a  more  steady  supply  of  labor,  that  the  quality  of  labor  has 
improved  and  the  earning  capacity  of  the  laborer  increased.  Lumber- 
mill  corporations  have  willingly  contributed  from  $1,000  to  $10,000 
toward  local  anti-malaria  campaigns,  and  state  it  pays  them  well  to 


62  MOSQUITO  ERADICATION 

make  such  an  investment.  Because  of  the  change  of  ideas  concerning 
the  cause  and  possibilities  of  prevention  of  malaria,  there  is  a  marked 
improvement  in  the  method  of  screening  of  houses  in  malarial  districts, 
and  the  percentage  of  houses  kept  efficiently  screened  has  increased 
very  largely.  In  sections  where  the  hotels  at  sea-shore  resorts  were 
formerly  filled  only  in  the  non-fever  season,  the  proprietors  report,  as  a 
result  of  malaria-control  measures,  they  now  have  all  the  business  they 
can  handle  throughout  the  entire  year. 

"Considering  the  fact  that  a  few  years  ago  hundreds  of  communities 
were  seriously  affected  and  with  no  apparent  relief  in  sight,  that  the 
public  in  general  had  no  visible  proof  of  the  possibilities  of  malaria 
eradication,  and  too  large  a  proportion  of  our  public  was  wrongly 
informed  regarding  the  cause  of  malaria,  it  is  gratifying  to  note  that  this 
year  over  a  hundred  of  these  same  places  have  decided  to  finance 
campaigns  for  malaria  elimination.  They  have  already  appropriated 
for  this  season's  work  nearly  20  times  as  much  as  the  original  annual 
Federal  appropriation,  1914-1917. 

"It  is  even  more  encouraging  to  note  that  there  is  a  strong  demand  for 
state  and  county  aid  along  these  lines,  and  that  such  support  has  already 
been  given  and  has  the  approval  of  the  public.  What  is  also  important 
is  that  a  large  part  of  the  public  now  realize  that  it  costs  them  much 
more  to  continue  to  suffer  and  support  the  financial  loss  caused  by 
malaria  than  it  does  to  eliminate  the  disease  from  their  community.'' 

ERADICATION   CHEAPER  THAN  ENDURING   MALARIA 

LePrince's  last  sentence  embodies  a  truth  that  should  be 
seriously  considered  by  every  community  that  suffers  from 
malaria.  The  demonstrations  already  described  in  this  chapter 
prove  that  the  average  town  can  free  itself  from  malaria  and 
kindred  mosquito-borne  diseases  and  the  annoyance  of  mosquitoes 
for  much  less  than  it  costs  to  endure  them. 

Estimates  of  the  cost  of  an  attack  of  malaria  vary,  but  it  is 
believed  that  Van  Dine's  estimate  of  6.42  adult  days'  loss  of 
time  per  average  reported  case  is  conservative.  No  matter  what 
the  wage  may  be,  the  loss  will  be  considerable.  If  to  this  loss 
be  added  the  loss  occasioned  by  decreased  efficiency,  both  before 
and  after  the  acute  attack,  the  physician's  bill  and  the  cost  of 
medicine,  it  is  apparent  that  the  average  cost  of  a  case  of  malaria 
will  not  be  much  below  $15  or  $20  and  may  be  considerably 
beyond  the  latter  figure.  In  addition  to  this,  there  is  another  big, 
though  not  apparent,  loss  occasioned  by  decreased  efficiency  of 
those  who  have  only  comparatively  slight  attacks  and  do  not 
consult  physicians. 


DEVELOPMENT  OF  CONTROL  MEASURES  63 

It  will  easily  be  seen  that,  where  the  infection  is  at  all 
considerable,  the  annual  loss  to  a  community  from  malaria  may 
reach  a  very  high  figure.  Take  Roanoke  Rapids  for  example. 
It  is  asserted  that  during  the  malaria  season,  75  per  cent  of  the 
population  of  4,100,  or  3,075  persons  suffered  from  malaria.  To 
be  conservative,  let  us  say  that  only  25  per  cent,  or  1,025  suffered 
from  it.  Again,  instead  of  putting  the  loss  resulting  from  each 
case  at  $20,  let  us  put  it  at  $10.  The  annual  loss,  then,  was 
$10,250,  nearly  three  times  what  the  first  year's  cost  of  eliminat- 
ing malaria  was. 

Take  Crossett.  Before  work  started,  the  malaria  calls  of 
physicians  totalled  2,502  in  a  single  year;  the  year  that  work 
started  the  calls  totalled  741;  the  difference  is  1,761  calls. 
Assuming  the  physicians  made  two  calls  to  a  case,  the  reduction 
effected  by  the  anti-mosquito  work  was  880  cases.  At  $15  a 
case,  the  monetary  value  of  the  work  was  $13,200.  Yet  the 
actual  cost  of  the  work  for  that  year  was  only  $2,506.40. 

Similar  conclusions  may  be  drawn  from  the  facts  given  in  the 
accounts  of  the  other  demonstrations.  And,  as  a  rule,  the  costs 
of  the  work  are  considerably  less  after  the  first  year. 

While  local  conditions  are,  of  course,  the  determining  factor 
in  regard  to  costs  of  anti-mosquito  campaigns,  it  is  believed  that, 
in  the  average  town,  the  first  year's  cost  should  not,  as  a  rule, 
much  exceed  $1  per  capita.  If  this  be  true,  it  is  clear  that  it 
will  pay  the  community,  on  a  dollar-and-cent  basis  alone,  to 
initiate  anti-mosquito  work  if  only  one  person  out  of  every  15  or 
20  be  infected  during  the  season.  This,  of  course,  does  not  take 
into  consideration  such  aspects  of  the  matter  as  comfort,  up- 
building the  health  of  the  community,  etc. 

SOME  TYPICAL  CAMPAIGN  COSTS 

The  following  table  gives  the  cost  of  anti-mosquito  campaigns 
conducted  in  towns  that  co-operated  in  the  1920  joint  demonstra- 
tion by  the  U.  S.  Public  Health  Service,  the  International  Health 
Board  and  the  Health  Departments  of  the  States  in  which  they 
are  situated:1 

1  Southern  Medical  Journal,  April,  1921. 


64 


MOSQUITO  ERADICATION 


State    and     town 


Area  in 

square 

miles 


Popu- 
lation, 
1920 


Total  cost 


Cost  per 

square 

mile 


Cost  per 
capita 


Alabama 

Dothan 

4.0 
4.0 
6.0 
4.0 
4.0 
4.0 

4.5 
3.5 
3.0 
4.0 

4.0 

12.5 

8.0 

4.4 
8.6 
4.5 

4.0 
4.0 
1.8 
2.5 
1.0 

3.2 
2.3 

5.5 

7.0 
8.0 
7.5 

3.8 

5.1 

4.0 
4.0 
6.0 
4.0 
1.5 
5.0 
3.0 
2.0 
6.0 
4.0 
1.5 
1.5 
1.0 
6.0 

0.6 
3.6 

10,300 
6,257 
5,000* 
1,000* 
1,000* 
3,500* 

5,500 
3,864 
2,865 
2.996 

1,908* 

11,555* 

8,196* 

21,782* 
12,675 
1,216* 

5,055* 

10,501* 

1 ,  050 

3,007 

411* 

5,700* 

2,100* 

11,300* 

2,211 

5,000* 

3,100* 

3,060* 
6,544 

1,081 
3,704 
6,299 
2,099 
1,200* 
2,741 
4,723 
1,258 
5,060 
2,348 
1,250* 
1,250* 
900* 
4,290* 

1,635 
840 

$     4,796.33 
3,327.90 
2,696.97 
2,092.50 
2,499. 15 
1,882.45 

2,355.85 
2,190.00 
1,660.00* 
2,778.79 

999. 85 
3,984.36 
4,452.02 

4,775.36 
9,040.00 
1,420.00 

3,059.69 
3,412.49 
2,019.09 
1,540.26 
1,088.60 

8,972.98 

4,980.00 

10,052.19 

29,400.00* 
7,460.77 
3,635.77 

1,850.00 
2,367.00* 

1,539.56 
799.05 
3,775.00* 
1,380.00* 

315.00 

2,250.00* 

1,622.01 

300.00 

3,000.00* 

1,863.15 

414.00 

302.  56 

520. 00 

889. 12 

3,636.32 
2,448.79 

$1,199.00 
832.00 
450. 00 
523.00 
625.00 
470.00 

523. 00 
626.  00 
553.00 
695.00 

250. 00 
318.00 
557.00 

1,080.00 

1,052.00 

315.00 

765.  00 
853.00 

1,120.00 
615.00 

1,089.00 

2,800.00 
2,165.00 
1,827.00 

4,200.00 
934.00 
485. 00 

485.00 
465.  00 

384.00 
200. 00 
627.00 
345.00 
210.00 
450.00 
541.00 
150.00 
500.  00 
466.00 
276.  00 
202.00 
520. 00 
140. 00 

6,050.00 
679.00 

$  0.47 

Eufala 

0.53 

Demopolis 

0  54 

Gantt's  Quarry 

Shelby 

2.09 
2.50 

Mignon 

0.54 

Arkansas 

Eldorado 

0.43 

Malvern 

0.57 

Searcy 

0.58 

Fordyce 

0.93 

Georgia 

Cairo 

0.52 

0.34 

Thomasville 

Louisiana 

Baton  Rouge 

Monroe 

0.54 

0.22 
0.71 

Bastrop 

1.16 

Mississippi 

Tupelo 

0.61 

Columbus 

Batesville 

0.33 
1.92 

Charleston 

Coffeeville 

0.51 
2.64 

North  Carolina 

Greenville 

Farmville 

Goldsboro 

South  Carolina 

Bamberg 

Chester 

Hartsville 

1.57 
2.37 
0.89 

13.30 
1.49 
1.17 

Tennessee 

Brownsville 

Dyersburg 

Texas 

Alto 

0.60 
0.36 

1.42 

Athens 

0.22 

Bryan 

0.60 

Calvert 

Groveton 

0.66 
0.26 

Hearne 

0.32 

Jacksonville 

0.34 

Livingston 

0.24 

Navasota 

0.59 

Rusk 

0.80 

Trinity 

0.33 

South  Groveton 

Rock  Creek  Lumber  Co. 
Cameron 

0.24 
0.58 
0.21 

Virginia 

West  Point 

2.22 

Virginia  Beach 

2.90 

Grand  total 

192.41 

199,319 

S155.845.32 

$808.00 

Grand  average 

$0.78 

*  Approximate. 

It  will  be  noted  that  at  32  out  of  the  45  towns  the  work  cost 
less  than  $1.00  per  capita.  Reducing  the  cost  per  square  mile 
to  cost  per  acre,  it  appears  that  the  average  cost  per  acre  was  only 
$1.26.     Apropos  of  this,  LePrince1  says: 


Southern  Medical  Journal,  April,  1921. 


DEVELOPMENT  OF  CONTROL  MEASURES  65 

"Investigations  that  have  taken  place  during  past  years  show  that  our 
richest  farms  in  the  best  part  of  our  country  are  paying  anywhere  from 
$2.50  to  $10.00  per  acre  per  year  as  a  malaria  tax.  Now  here  are  200 
square  miles,  where  the  cost  per  acre  was  $1.26. 

"Public  sentiment  unquestionably  is  favorable  to  the  control  of 
malaria  by  drainage  on  a  big  scale;  and  drainage,  supplemented  by  fish 
control  and  other  measures  is  not  only  feasible,  but  it  will  be  done 
because  it  is  what  the  people  desire." 


CHAPTER  IV 
INITIATING  THE  CAMPAIGN 

NEED  FOR  STATISTICS 

Although,  in  any  community  where  mosquitoes  are  numerous, 
their  eradication  solely  as  a  source  of  annoyance  is  probably 
well  worth  the  cost  of  the  campaign,  it  should  be  borne  in  mind 
that  in  most  communities  the  campaign  is  launched  primarily 
as  a  health  measure,  with  the  object  of  reducing  the  toll  of 
malaria  and  other  mosquito-borne  diseases. 

Where  such  a  campaign  is  under  consideration,  it  is  necessary 
to  have  some  figures  of  the  incidence  of  the  mosquito-borne 
diseases  in  order  to  show  the  necessity  for  the  campaign  and  thus 
obtain  the  money  required  to  conduct  it.  It  is  also  advisable 
to  be  able  to  show  the  reduction  in  disease  resulting  from  the 
work,  so  that  the  community  will  know  that  the  expenditure  was 
a  profitable  one  from  a  financial  viewpoint. 

In  order  to  do  this,  the  director  must  have  at  hand  reliable 
statistics  covering  the  incidence  of  the  mosquito-borne  diseases 
for  one  or  more  years  prior  to  the  initiation  of  the  campaign, 
as  well  as  those  covering  the  incidence  of  the  same  diseases  during 
the  campaign.     There  must  be  some  basis  of  comparison. 

Of  course,  the  residents  of  the  community  will  be  able  to  get 
some  idea  of  the  efficacy  of  the  work  by  the  absence  or  presence 
of  mosquitoes  in  general.  However,  it  is  well  recognized  that 
it  may  be  possible  to  reduce  malaria  very  considerably,  and  still 
have  numerous  non-Anopheline  mosquitoes  present.  While 
anti-malaria  campaigns  as  a  rule  include  eradication  of  all 
mosquitoes,  it  is  well  known  that  certain  other  common  domestic 
mosquitoes  are  much  more  difficult  to  control  than  the  Anopheles. 

COLLECTION  OF  STATISTICS 

If  the  community  is  in  a  State  where  malaria  and  the  other 
mosquito-borne  diseases  are  reportable  or  notifiable,  records  of 
the  past  incidence  of  the  diseases  may  be  obtained  from  the 
State  Health  Department,  the  Registrar  of  Vital  Statistics  or 
other  official  source,     If,  however,  the  community  is  in  a  State 

66 


IXITIATIXG  THE  CAMP  Aid  X 


67 


where  these  diseases  are  not  reported,  it  will  be  necessary  to  get 
the  figures  from  other  sources.  In  this  case,  a  beginning  should 
be  made  as  far  in  advance  of  the  date  of  opening  of  the  campaign 
as  possible. 

In  an  anti-malaria  compaign  with  which  the  writer  was 
connected  in  1920,  no  figures  as  to  the  incidence  of  malaria,  were 
available  from  official  sources.  It  was,  therefore,  necessary  to 
get  some  figures  from  the  physicians  of  the  community  as  to  the 
incidence  of  the  disease  during  the  preceding  2  years. 

Owing  to  the  difficulty,  in  cases  where  the  illness  was  pro- 
longed, of  determining  whether  the  patient  was  suffering  from 
one  original  infection  or  successive  ones,  it  was  considered 
preferable  to  obtain  from  the  physicians  figures  as  to  their  calls 
and  consultations  for  malaria  rather  than  as  to  cases. 

Accordingly,  each  physician  of  the  community  was  called  on, 
the  situation  explained  to  him  and  a  blank  left  with  him,  to  be 
filled  out  promptly  with  data  covering  his  malaria  practice  for 
1918  and  1919  and  returned  to  the  director  of  the  campaign. 
The  blank  form  is  reproduced  below. 


FORM  NO  1 . 


1920. 


,  Director, 

Anti-malaria  Campaign. 
Dear  Sir: — 

In  compliance  with  your  request,  I  am  giving  below  a  summary  of  malaria 
calls  made  by  me  during  1918  and  1919.  Asterisks  indicate  that  the 
figures  are  approximate  only. 

Number  of  Calls  for  Malaria 


Month 

1918 

1919 

1920 

White 

Colored 

White      Colored 

White      Colored 

January 

February 

March 

April 

May 

June 

Julv 

August 

September 

October 

November 



December 

1 

M.D. 


68 


MOSQUITO  ERADICATION 


Each  physician  was  left  a  number  of  postcards  upon  which  to 
report  monthly  the  number  of  calls  he  had  made  upon  persons 
suffering  from  malaria  within  the  area  of  operations.  These  were 
entered,  as  soon  as  received  each  month,  in  the  1920  column  of  the 
No.  1  form  sent  in  by  that  physician.  In  this  way  the  efficacy 
of  the  control  measures  each  month  was  visible  at  a  glance. 

To  get  the  total  for  the  town,  each  physician's  figures  by 
months  for  the  years  1918  and  1919,  and  also  for  1920  as  they  were 
received,  were  added  together  on  another  blank  similar  to  Form 
No.  1,  thus  giving  at  a  glance  the  situation  for  the  town  as  a 
whole. 

Where  other  mosquito-borne  diseases  are  a  factor,  statistics 
regarding  them  should  be  collected  also. 

In  cases  where  it  is  impracticable  to  obtain  the  desired  infor- 
mation from  the  physicians  of  the  community,  a  house-to-house 
malaria  census  may  be  taken.  This  method  probably  will  not 
be  so  accurate  as  the  method  of  obtaining  figures  from  the 
physicians  for  obvious  reasons,  but  will  serve  as  a  basis  for 
comparison. 

The  following  malaria  census  card  is  suggested  as  suitable  for 
use  in  ordinary  cases: 

FORM  NO.  2 
Malaria  Census 


(city) 


(date) 


Head  of  House Address No.  in  Family 

How  Long  in  City Previous  Address 

House  Screened Condition  of  Screens 

Potential  Breeding  Places  on  Premises 


Malaria  History 

Years 

Cases  in 
family 

Deaths 

Supposed 
origin  of 
infection 

Total 
days 
time 
lost 

Total 

calls  of 

physician 

Re- 
marks 

INITIATING  THE  CAMPAIGN  69 

Where  practicable,  data  for  the  2  years  previous  should  be 
obtained;  if  this  is  not  possible  figures  for  the  preceding  year 
will  do.  At  the  conclusion  for  the  season's  work,  a  second  census 
should  be  taken,  using  the  same  card  for  the  same  house  and 
recording  the  second  results  below  the  first.  This  will  show  the 
comparison  in  incidence  for  each  family,  before  and  after  initiating 
the  work. 

THE  SURVEY 

As  soon  as  it  has  been  determined  by  means  of  the  collection 
of  statistics  relative  to  the  incidence  of  the  mosquito-borne 
diseases  in  the  community,  that  an  anti-mosquito  campaign 
would  be  justified,  the  next  step  is  to  make  a  survey  of  the  pro- 
posed area  of  operations,  with  a  view  to  ascertaining  the  probable 
cost  of  such  a  campaign.  If  at  all  possible,  this  should  be  done 
by  a  sanitary  engineer  familiar  with  costs  of  this  kind  of  work. 
Frequently  State  Departments  of  Health  will  send  an  engineer 
to  make  such  a  survey  gratis. 

The  following  suggested  mode  of  procedure  in  making  the 
survey  and  estimate  is  taken  from  the  instructions  issued 
sanitary  engineers  engaged  in  the  co-operative  anti-malaria 
demonstration  work  of  the  U.  S.  Public  Health  Service  and  the 
International  Health  Board: 

"Assuming  that  it  is  concluded,  from  information  gathered,  that  the 
making  of  a  survey  is  worth  while,  obtain,  if  available,  a  map  of  the  area 
involved  or  make  a  copy  of  an  existing  one.  If  none  has  been  pre- 
viously made,  you  will  make  a  sketch  map  as  you  proceed.  (Maps 
generally  may  be  obtained  from  the  city  authorities;  if  not,  an  insurance 
map  may  be  borrowed  from  a  fire  insurance  agent.) 

"On  this  map,  mark  all  water-courses,  swamps,  ponds,  ditches,  wet 
lands,  land  subject  to  overflow  and  other  wet  places  or  possible  sources 
of  mosquito-breeding.  On  flat  lands,  make  inquiry  as  to  how  long  water 
stands  thereon  in  wet  periods;  look  for  vegetation  that  is  indicative  of  a 
high  water  table.  Let  the  map  extend  to  about  half  a  mile  from  the 
residences  on  the  outskirts  of  town. 

WHAT  TO  OBSERVE 

"It  is  next  necessary  to  note  the  ditching  and  filling  and  clearing  or 
regrading  (of  streams  and  old  ditches)  that  is  essential  and  that  which 
will  probably  be  necessary.  It  is  not  advisable  to  make  estimates  for 
ditching  from  observations  immediately  after  rain-storms.  The  infor- 
mation must  be  carefully  gathered;  the  character  of  soil,  amount  of 


70 


MOSQUITO  ERADICATION 


roots  to  be  encountered,  extra  ditches  to  care  for  seepage  outcrops, 
widths  of  ditches  or  streams,  etc.,  must  be  considered  in  estimating 
costs.  Go  along  each  water-course  and  its  branches,  estimate  the 
lengths  by  pacing,  mark  them  on  the  map  and  note  at  the  same  time  your 
estimated  cost  of  such  brush-clearing,  regrading,  ditching,  etc.,  as^is 
necessary,  step  by  step.  Where  ponds,  marshes  and  other  wet  places 
necessitate  the  installation  of  new  ditches,  indicate  them  on  the  map, 
and  enter  in  your  notes  the  extent  and  cost  of  each. 


(Photos  by  E.  B.  Johnson,  C.E.) 
Fig.  50. — Brushing  streams.     The  objects  are  to  improve  fish  control,  facilitate 

inspection  and  eliminate  shade. 

"On  flat  territory  during  dry  periods,  it  is  frequently  difficult  to  judge 
of  the  amount  of  water  that  may  stand  intermittently  on  the  land,  and  it 
is  advisable  to  note  the  character  of  the  vegetation  and  make  frequent 
inquiry  of  the  native  population.  If  you  can  get  a  man  well  acquainted 
with  the  locality  to  accompany  you,  so  much  the  better. 

"When  the  mapping  of  all  breeding-places  and  collections  of  water  is 
concluded  and  the  data  collected,  sum  up  the  different  classes  of  excava- 
tion, brushing,  etc.,  and  make  an  itemized  statement  thereof  to  accom- 
pany the  report  of  the  survey.  Determine  the  local  cost  of  kerosene  and 
oil,  delivered,  find  out,  if  necessary,  what  transportation  could  be  ob- 
tained from  the  town  for  oil  distribution,  ascertain  whether  ditches  and 
soil  would  warrant  use  of  a  ditching  plough,  what  size  ditching  gang  is 
necessary  and  what  number  of  men  will  be  needed  for  oiling  and  main- 
tenance (of  ditches  and  streams).  As  a  rule,  the  brushing  (clearing)  of 
one  bank  of  a  ditch  (or  stream)  is  sufficient  for  oiling  and  inspection 
purposes." 


INITIATING  THE  CAMPAIGN 


71 


THE  ESTIMATE  OF  COST 

When  the  data  mentioned  have  all  been  collected,  work  on  the 
estimate  may  be  started.  The  instructions  already  quoted 
provide  for  estimation  of  the  costs  of  brushing  streams  or  existing 
ditches  (one  side  only)  clearing  streams  or  existing  ditches 
(clearing  channel  of  obstructions,  connecting  pools  in  stream 
bod,  etc.)  and  of  new  ditching,  as  follows: 

FORM  XO.  3 


Waterway 

Length, 
feet 

Brushing, 
feet 

Clearing, 
feet 

Ditching, 

feet 

A 

A-l 

A-2 

5,000 

1,000 

750 

475 

230 

4,600 
200 

1.000 
250 

B 

B-l 

per  lineal  foot . 

475 
230 

Totals .... 
Average  cost 
Cost 

7,455 

4,800 
.01 

$48 . 00 

1,250 
.03 

$37 . 50 

705 

.05 

$35.25 

Note. — A-l,  A-2,  etc.,  indicate  branches  of  Ditch  or  Stream  A  shown  on 
map.  The  lineal  foot  costs,  given  above  for  the  sake  of  illustration,  should 
by  no  means  be  taken  as  applicable  to  all  conditions. 

The  above  estimate  gives  the  cost  of  the  new  work  necessary — 
in  other  words,  the  construction  cost. 

The  next  thing  required  is  an  estimate  of  the  maintenance 
cost  for  the  season — that  is,  the  cost  of  keeping  the  ditches, 
streams,  etc.,  in  shape.  This  consists  of  keeping  grass,  weeds, 
floating  matter  and  other  obstructions  out  of  them.  Owing  to 
the  great  variations  encountered,  due  to  differences  in  topography, 
soil,  precipitation,  etc.,  it  is  impossible  to  give  any  general  rate 
for  this  work. 

The  next  thing  that  requires  attention  is  estimation  of  the 
cost  of  the  oil  that  will  be  needed  and  the  cost  of  applying  it, 
including  transportation.  Some  general  information  on  oiling 
jobs  is  given  in  the  chapter  relating  to  oiling. 

The  cost  of  control  by  means  of  fish  should  next  be  calculated. 
This  is  variable,  according  to  local  conditions  and  the  scope  of 
the  work.  It  should  include  costs  of  collection,  aquaria,  distri- 
bution, protection,  pond  and  stream  cleaning,  etc. 


72  MOSQUITO  ERADICATION 

If  the  campaign  is  to  include  screening,  the  probable  amount 
of  the  work  should  be  figured  out  and  an  estimate  of  the  total 
cost  made.  Figures  on  screening  costs  may  be  found  in  the 
chapter  on  screening. 

Individual  jobs  of  magnitude  should  be  listed  next.  They 
may  comprise  such  measures  as  filling  holes  and  other  odd  jobs. 

A  sufficient  allowance  should  be  made  for  cost  of  tools  and 
equipment.  This  can  generally  be  estimated  as  soon  as  the 
size  of  the  labor  force  is  decided  upon. 

Another  item  to  be  considered  is  cost  of  general  direction  and 
inspection  for  the  season.  This  should  include  wages  and 
salaries  of  the  director,  inspectors,  clerical  help,  etc.,  and  cost 
of  any  transportation  furnished  them  for  directing  or  inspection 
purposes. 

Then,  to  provide  for  unforeseeable  factors,  such  as  floods, 
long-continued  bad  weather  and  the  like,  a  contingency  fund 
should  be  allowed  for.  The  writer  usually  estimates  this  at  10 
per  cent  of  the  total  cost  of  the  work. 

These  various  items  should  be  combined  into  one  general 
estimate,  which  would  be  approximately  as  follows  for  a  cam- 
paign in  a  typical  small  town. 

FORM  NO.  4 

Brushing,  44,800  lineal  feet  at  0.01 $     448.00 

Clearing,  21,250  lineal  feet  at  0.03 637 .  50 

Ditching,  17,705  lineal  feet  at  0.05 885.25 

Maintenance,  77,455  lineal  feet  at  0.005 387.28 

Oiling,  5,000  gallons  oil  at  0.10 500.00 

Applying  oil,  1  man  4  months  at  $90 360.00 

Hauling  oil,  1  horse  and  rig,  4  months  at  $50 200 .  00 

Fish  control,  1  man  4  months  at  $90 360 .  00 

1  horse  and  rig,  4  months  at  $50 200.00 

Aquatic  plant  removal  at  Smith's  Lake 100.00 

Individual  jobs,  cutting  brush  and  weeds  at  marsh 180.00 

Filling  big  hole  at  Jones  and  Brown  streets 75 .  00 

Tools  and  equipment,  2  sprayers  at  $12.50 25.00 

10  picks  and  10  shovels 40.00 

5  faucets  for  oil-barrels 2 .  00 

Miscellaneous  articles 25 .  00 

Inspection,  1  inspector  8  months  at  $100 800 .  00 

Total $5,225.03 

Contingency  fund,  10  per  cent 522 .  50 

Grand  total $5,747.53 


INITIATING  THE  CAMPAIGN  73 

Note. — It  is  presumed  here  that  one  man  with  a  horse  and  rig  will  be  able 
to  do  both  the  oiling  and  fish  work,  giving  about  half  of  his  time  to  each. 
For  this  reason,  the  total  engagement  of  8  months  for  the  man  and  the  horse 
and  rig  is  split  up  into  4  months  at  oiling  and  4  months  at  fish  work. 

Figures  here  given  for  the  sake  of  illustration  should  in  no  way  be  relied 
upon  as  unit  costs  for  work. 

QUESTIONS  OF  POLICY 

With  the  survey  completed  and  a  careful  estimate  made  as 
above  outlined,  the  next  step  is  to  get  the  money  for  the  cam- 
paign, but  before  efforts  are  made  in  this  direction,  a  definite 
policy  as  to  what  part  of  the  cost  of  eradicating  breeding  places 
on  private  property  should  be  met  'by  the  property-owner  or 
tenant  and  what  part  should  be  defrayed  out  of  the  anti-mosquito 
fund  must  be  decided  on. 

This  question  must  be  definitely  settled  at  this  point,  because 
it  is  a  certainty  that  a  very  large  portion  of  the  work  required 
will  be  on  private  property.  If  the  public  funds  are  to  be  spent 
without  restrictions  on  private  property,  the  entire  amount  of 
the  estimate  should  be  asked  for.  If,  however,  private  property- 
owners  are  to  be  compelled  to  do  their  own  work,  the  sum  required 
for  the  prosecution  of  the  campaign  will  be  greatly  lessened.  It 
will,  of  course,  be  necessary  to  put  the  public  property,  such  as 
streets,  parks,  municipal  grounds,  etc.,  in  shape  and  keep  it  in 
shape,  as  well  as  to  maintain  an  adequate  inspection  force,  but 
most  of  the  heavy  items,  such  as  drainage,  oiling,  etc.,  will  be 
eliminated. 

In  most  of  the  demonstration  projects  with  which  the  writer 
has  been  connected,  it  has  been  customary  to  do  at  least  a  part 
of  the  work  necessary  to  prevent  breeding  on  private  property. 
In  some  cases,  everything  was  done  without  cost  to  the  property- 
owner;  in  others,  the  cost  of  drainage,  etc.,  was  charged  up  to 
them,  but  oiling,  fish  control,  etc.,  were  free;  in  still  others, 
routine  oiling,  fish  control  and  drainage  were  free,  but  property- 
owners  were  expected  to  look  after  their  own  cisterns,  fish-ponds 
and  other  special  breeding  places. 

There  are  many  angles  to  this  question,  which  must  be  care- 
fully thought  out.  The  average  property-owner  does  not  want 
to  bother  himself  with  drainage,  inspections,  oiling,  etc.  nor  can 
he  be  depended  upon  to  do  such  work  thoroughly.  And  too 
many  prosecutions  will  arouse  antagonism  toward  the  campaign 


74  MOSQUITO  ERADICATION 

SUGGESTED  POLICY  TOWARD  PROPERTY-OWNERS 

It  is  the  belief  of  the  writer  that  some  sort  of  compromise  is 
best.  It  would  appear  to  him  that  oiling,  fish  control  and  other 
routine  measures  rendered  necessary  by  the  presence  of  natural 
streams,  etc.,  by  rains  or  other  causes  not  due  to  the  fault  of  the 
property-owner  should  be  carried  out  by  the  city  forces  without 
cost  to  him.  On  the  other  hand,  he  should  be  compelled  to 
remedy  any  condition  originating  through  his  negligence, 
the  continuance  of  which  would  cause  extra  work  to  the  city 
forces,  such  as  letting  his  drain  pipes  leak  and  form  a  pool  under 
his  house,  having  unscreened  or  untreated  water-barrels  about, 
letting  his  pond  grow  up  with  aquatic  plants  so  as  to  impede 
control  by  fish,  failing  to  do  necessary  drainage  work  bearing 
a  reasonable  relation  to  the  value  of  the  property,  etc.  In  case 
of  failure  to  do  the  work  after  reasonable  notice,  it  should  be 
done  by  the  anti-mosquito  forces  and  its  cost  charged  up  to  him. 

It  is  not  suggested  that  there  be  adopted  a  set  rule  in  the  matter 
under  consideration,  since  all  sorts  of  situations  are  bound  to 
arise  which  cannot  be  forseen.  The  director  should  be  left  a 
certain  latitude  to  meet  these  situations.  Thus,  it  would  be 
unreasonable  to  ask  the  owner  of  a  tract  of  swamp  land  on  the 
outskirts  of  town,  worth,  say,  $5  an  acre,  to  spend  $25  an  acre  to 
drain  it.  There  must  be  power  to  co-operate  and  a  willingness 
to  meet  the  situation  on  a  fifty-fifty  basis.  On  the  other  hand, 
unless  there  is  some  general  policy  determined  upon,  there  is 
danger  that  too  much  will  be  asked  of  willing  citizens,  while 
the  unwilling  ones  get  the  benefit  of  the  work  without  having 
done  their  "bit." 

RAISING  FUNDS 

Assuming  that  a  definite  decision  is  made  along  the  lines 
suggested  by  the  writer,  and  that  the  estimate  has  been  made 
accordingly,  the  next  step  is  to  get  the  money.  This  should  be 
obtained  preferably  from  the  city,  since  the  work  is  for  the  benefit 
of  all  citizens  alike.  Furthermore,  protecting  the  health  of  its 
citizens  is  one  of  the  first  duties  of  a  municipality. 

The  first  step  is  for  those  interested  in  the  matter  to  put  it 
before  the  city  authorities.  The  incidence  of  the  diseases 
locally,  the  large  economic  loss  they  cause  and  the  saving  to  the 
community  in  dollars  and  cents  in  eradicating  the  diseases  should 
be  fully  outlined.     If  possible,  the  City  Health  Officer  and  the 


INITIATING  THE  CAMPAIGN  75 

leading  physicians  should  handle  the  references  to  the  incidence 
of  the  diseases,  while  the  director  or  a  sanitary  engineer  of  the 
State  Department  of  Health  should  vouch  for  the  estimates  and 
recount  achievements  against  mosquitoes  elsewhere. 

At  the  same  time  the  proposed  anti-mosquito  ordinance  should 
be  submitted  with  a  request  that  it  be  adopted.1 

As  soon  as  the  matter  has  been  presented  to  the  council,  a 
publicity  campaign  should  be  started  with  the  object  of  bringing 
home  to  the  tax-payers  the  advantages  of  the  proposed  work, 
so  that  they  may  intelligently  indicate  to  the  council  their  desires 
in  the  matter.  Newspaper  articles,  illustrated  lectures  and 
other  methods  of  publicity  should  be  among  the  measures  used. 

By  the  time  the  council  meets  again,  a  good  delegation  of 
citizens  should  be  prepared  to  go  before  it  and  urge  making  of 
the  appropriation  and  adoption  of  the  ordinance.  If  the  money 
is  available,  and  the  council  sees  that  the  citizens  want  the 
campaign,  there  should  be  no  further  difficulty. 

However,  as  is  frequently  the  case,  the  council  may  be  in  favor 
of  the  campaign,  but  may  not  have  enough  money  available, 
especially  if  the  appropriations  for  the  year  have  already  been 
made.  In  this  case,  it  may  be  possible  to  have  the  council 
adopt  the  ordinance  and  appropriate  as  much  as  is  available, 
provided  enough  money  can  be  obtained  elsewhere  to  meet 
the  estimate. 

In  this  case,  the  protagonists  of  the  campaign  will  have  to 
raise  the  balance  from  other  sources.  This  is  generally  practi- 
cable, if  the  publicity  work  has  been  effective,  so  that  the  people 
really  know  what  is  proposed.  The  writer  has  found  that 
county  authorities,  chambers  of  commerce,  women's  clubs, 
individual  citizens  and  corporations  and  even  church  and 
fraternal  organizations  will  contribute  liberally  for  anti-mosquito 
work,  provided  they  are  convinced:  (1)  that  the  project  is 
feasible;  (2)  that  it  is  economically  advantageous;  and  (3)  that 
the   persons   proposing  it   know   what   they  are   talking  about. 

HANDLING  THE  FUNDS 

Once  the  balance  is  raised,  it  should  be  turned  over  to  the 
proper  city  official,  to  form,  with  the  sum  appropriated  by  the 
city,  the  anti-mosquito  fund.  The  director  of  the  campaign 
should  have  absolutely  a  free  hand  in  expending  this  money 

1  An  approved  anti-mosquito  ordinance  is  printed  as  Appendix  B. 


76  MOSQUITO  ERADICATION 

and  in  conducting  the  campaign  generally,  although,  of  course, 
all  payments  should  be  made  by  the  city  disbursing  officer. 
The  agreement  made  by  the  U.  S.  Public  Health  Service,  the 
International  Health  Board  and  the  State  Health  Departments 
of  the  States  which  participated  in  the  malaria-control  demonstra- 
tions, with  the  towns  in  which  the  demonstrations  were  made, 
provided  as  follows  with  reference  to  handling  of  the  anti-mos- 
quito fund: 

"It  is  understood  that  the  city's  appropriation  will  be  made  available 
not  later  than  March  1,  in  a  lump  sum,  to  be  known  as  the  'Appropria- 
tion for  Malaria  Control  Work.'  It  will  be  deposited  in  a  local  bank  and 
be  subject  to  draft  by  the  Mayor  as  provided  for  below. 

(a)  "The  city  council  or  commissioners  will  empower  the  Mayor  or 
other  local  authority  to  issue  drafts  against  the  appropriation  account, 
upon  certification  by  the  Sanitary  Engineer  or  other  duly  accredited 
officer. 

(b)  "All  bills  and  vouchers  will  be  presented  to  the  Sanitary  Engineer 
for  his  certification  for  payment.  This  certification  will  be  made  only 
after  the  accuracy  of  the  time-books  and  bills  has  been  verified. 

(c)  "The  salary  of  the  inspector  and  the  wages  of  other  employes  will 
be  determined  from  time  to  time,  and  will  be  submitted  to  the  Mayor 
for  his  approval. 

(d)  "Changes  in  the  salaries  of  any  of  the  employes  will  be  made  only 
upon  recommendation  by  the  Sanitary  Engineer. 

(e)  "A  financial  statement  will  be  made  at  the  end  of  each  month  by 
the  Mayor  or  his  legal  representative  to  the  city  council  or  board  of 
commissioners  and  to  the  Sanitary  Engineer. 

(/)  "All  accounts  will  be  kept  in  a  multiple  column  cash-book  furnished 
by  the  city,  and  each  item  will  be  charged  to  its  appropriate  item  number 
as  given  in  the  estimates  of  the  Sanitary  Engineer. 

(g)  "  Drafts  for  the  payment  of  laborers  will  be  issued  by  the  Mayor  or 
his  legal  representative,  after  certification  by  the  Sanitary  Engineer,  and 
for  all  money  paid  to  them  the  local  inspectors  and  laborers  will  be 
required  to  sign  receipts  in  duplicate,  one  copy  to  be  retained  in  the 
office  of  the  Mayor  and  the  other  given  to  the  Sanitary   Engineer." 

OBTAINING  CO-OPERATION 

The  financial  details  all  settled,  the  next  step  is  to  make  arrange- 
ments with  property-owners  in  so  far  as  possible  for  co-operation 
in  conducting  the  campaign.  In  almost  every  town,  the  rail- 
roads, street  and  road  departments,  industrial  concerns  and 
many  individuals  with  large  mosquito-breeding  problems  will 


INITIATING  THE  CAMPAIGN 


11 


be  glad  to  co-operate  in  a  large  measure  to  make  the  campaign 
a  success. 

In  connection  with  this  feature  of  the  work,  Derivaux1  says: 

"Public  works,  and  more  especially  railroad  construction  operations, 
have  long  been  notorious  for  their  incidental  contributions  to  malaria 
hazards  by  creating  conditions  favoring  the  development  of  Anopheles 
mosquitoes.  Among  these  conditions  may  be  mentioned:  Badly 
located  and  undrained  borrow-pits,  at  times  uninterruptedly  traversing 
thickly    settled     communities;     improperly    cut    right-of-way   ditches 


Fig.   51. 


(Photo  by  E.  H.  Mayooii,  C.  E.) 
-Leaky  railway   water  tower.     Mosquitoes   bred   here  in   abundance 
before  control  work  started. 


that  have  not  been  provided  with  outlets;  improperly  placed  culverts 
and  crossings,  installed  possibly  with  a  view  to  saving  a  few  feet  of  pipe 
or  yards  of  masonry,  but  preventing  the  off-flow  of  normal  and  storm 
waters  and  at  times  interfering  with  an  entire  system  of  natural  surface 
drainage;  inadequate  pro  vision  for  drainage  behind  or  through  embank- 
ments and  fills  across  valleys,  resulting  in  the  impounding  of  water  or 
interference  with  the  normal  off-flow  of  a  natural  watershed;  installation 
of  leaky  water-towers  or  failure  of  provision  to  carry  off  their  over-flow." 

It  appears  well  to  summarize  in  some  detail  the  steps  which 
railroads  can  take  in  dealing  with  the  mosquito-borne  diseases. 
Derivaux2  suggests  the  following: 

(a)  "Old  Construction  Conditions. — Correction  or  alleviation  of 
Anopheles-breeding     and     malaria-producing     conditions     created     in 

1  "The  Relation  of  the  Railroads  in  the  South  to  the  Problem  of  Malaria 
and  Its  Control,"  U.  S.  Public  Health  Service,  1918. 

2  "The  Relation  of  the  Railroads  in  the  South  to  the  Problem  of  Malaria 
and  Its  Control,"  U.  S.  Public  Health  Service,  1918. 


78 


MOSQ  UI  TO  ERA  DICA  TION 


connection  with  previous  construction  by:  Drainage  or  filling  of  borrow 
pits  and  low  areas  where  practicable;  proper  provision  for  drainage 
(in  a  sanitary  sense)  behind  embankments  and  fills  across  valleys; 
replacing  to  true  gradient  of  culverts  where  necessary;  drainage  or  other 
provision  for  care  of  over-flow  waters  at  tanks  and  towers;  clearing  of 
weeds  and  refuse  at  regular  intervals  (supplemented  by  oiling,  if  needed) 
from  right-of-way  ditches,  especially  in  and  adjacent  to  settlements. 
(b)  "New  Construction  Conditions. — Consideration  of  sanitary  features 
in  connection  with  new  construction  works ;  that  is  prevention  or  correc- 
tion of  conditions  menacing  the  health,  especially  of  settlements   and 


******  -iMm 

*:m               .  1  a* 

*Lr. 

- 

■ 

» •  ^*,          •  -            . 

Fig.  52. — A  culvert  properly  placed;  it  is  neither  too  low  nor  to< 

can  form  about  it. 


high.      Xo  pool 


communities.  To  this  end,  consultation  should  be  had  with  the  sani- 
tary or  medical  departments  before  construction  is  begun.  Preference 
should  invariably  be  given  to  sanitary  works  which  will  influence  as 
large  a  number  of  individuals  as  possible." 


OTHER  POSSIBLE  SOURCES  OF  AID 

The  same  considerations  apply,  in  large  measure,  to  street 
and  road  departments. 

Industrial  plants  often,  through  carelessness  or  ignorance, 
cause  conditions  favorable  to  mosquito-breeding.  Cisterns  and 
fire-barrels  may  be  unscreened  or  untreated,  water  may  be 
allowed  to  enter  under  the  buildings,  drainage  may  be  neglected, 
processes  that  may  with  little  cost  be  modified  may  cause 
abundant  breeding. 

Private  individuals  may  have  large  problems  in  swamp  areas, 
in  swimming,  recreation  or  fish  ponds,  cess-pools,  etc. 

In  all  the  above-mentioned  cases,  the  director  should  call  on 


INITIATING  THE  CAMPAIGN  79 

• 
the  person  in  charge,  point  out  the  necessity  of  complying  with 
the  anti-mosquito  ordinance,  make  suggestions  as  to  the  best 
methods  to  follow,  give,  if  desirable,  some  idea  of  the  cost  and 
offer  free  supervision.  In  case  the  problem  is  one  of  considerable 
magnitude,  in  relation  to  the  value  of  the  property,  it  may  not 
be  amiss  to  offer  to  participate  in  doing  the  work. 

It  has  been  the  writer's  experience  that,  in  most  cases,  people 
will  voluntarily  co-operate  along  the  lines  indicated,  if  the  matter 
is  properly  placed  before  them.  In  cases  where  they  will  not, 
prominent  local  persons  may  exert  pressure  upon  them.  If 
this  fails,  the  only  alternative  is  prompt  prosecution. 

PLANNING    THE    WORK 

When  the  above-mentioned  canvass  of  the  situation  is  com- 
pleted, the  director  of  the  campaign  will  have  a  pretty  good  idea 
of  what  work  he  will  have  to  do — that  is,  how  much  drainage, 
oiling,  etc.,  will  have  to  be  done  by  his  own  forces.  The  next 
step  is  to  lay  plans  for  doing  it  seasonably  and  effectively. 

It  is  a  good  idea  to  start  the  actual  work  early.  In  the  Public 
Health  Service  demonstrations  in  the  South,  it  was  generally 
the  rule  to  begin  active  work  by  March  1  or  shortly  thereafter. 

In  planning  the  work,  it  should  be  remembered  that  work 
which  will  benefit  the  largest  number  of  people  should  be  done 
first.  Hence,  problems  in  the  center  of  town  should  ordinarily 
be  tackled  before  those  on  the  outskirts. 

As  a  general  rule,  drainage  should  be  completed  as  early  as 
possible,  since  the  earlier  it  is  done,  the  less  will  be  the  amount 
of  oiling  required.  Furthermore,  with  the  direction  of  the  drain- 
age gang  off  his  hands  early,  the  director  will  have  more  time  for 
inspection  and  supervision  of  oiling  and  fish  control  just  as  these 
matters  are  becoming  of  greater  importance. 

If  active  work  is  to  start  by  March  1,  enough  laborers  should 
be  put  on,  if  practicable,  to  complete  the  drainage  work  in  not 
more  than  3  months,  since,  by  June  1,  the  director  will  have 
enough  other  problems  before  him  to  keep  him  busy. 

If  there  is  much  drainage  to  do,  two  or  more  gangs  of  laborers 
should  be  organized,  each  gang  having  its  own  foreman.  In 
this  way,  it  is  possible  to  compare  the  work  of  each  gang,  so  that 
poor  men  may  be  weeded  out.  The  principle  of  competition 
or  rivalry  also  may  be  utilized  in  this  way  to  hasten  the  work. 

At  the  same  time,  an  inspection,  oiling  and  fish  control  service 


80 


MOSQUITO  ERADICATION 


should  be  instituted,  the  size  depending  upon  the  amount  of 
of  work  and  the  area  of  operations.  Generally  speaking,  this 
service  should  be  organized  in  such  manner  that  immediately 
an  inspector  discovers  some  situation  which  needs  remedying, 


Fig.   53. — Above,   large   pool   of   stagnant   water,    affording   an   ideal    breeding- 
place  for  mosquitoes.     Below,  same  pool  drained. 

the  appropriate  action  is  taken  without  delay,  be  it  emergency 
drainage  that  is  required,  weekly  oiling  or  stocking  a  place 
with  fish. 

PERSONNEL 

Generally  speaking,  the  man  in  charge  of  the  drainage  work 
should  have  had  some  experience  as  a  labor  foreman,  preferably 


INITIATING  THE  CAMPAIGN  81 

in  earth-work.  This  does  not  mean,  however,  that  he  will  not 
need  careful  drilling  in  the  objectives,  methods  and  management 
of  anti-mosquito  drainage  work.  He  should  also  be  given  some 
idea  as  to  the  costs  of  this  class  of  work. 

For  the  first  few  weeks  at  least,  the  director  himself  should 
lay  out  the  ditches.  He  should  also  frequently  inspect  the  work 
to  assure  himself  that  money  is  not  being  wasted  by  divergence 
from  his  instructions. 

It  is  the  inspection  staff,  however,  that  should  be  picked  with 
the  utmost  care.  An  inspector  must  be  tactful,  honest,  energetic  ; 
he  must  also  have  a  good  working  knowledge  of  mosquito  eradi- 
cation in  general,  so  that  when  he  uncovers  a  breeding  place,  he 
will  know  at  once  what  measures  to  take  in  dealing  with  it, 
whether  to  drain,  oil  or  stock  with  fish.  He  should  also  be  able 
to    identify   at    once    any    of    the    disease-bearing   mosquitoes. 

If  the  inspector  is  not  tactful,  he  will  get  the  campaign  "in 
wrong;"  if  he  is  lazy  and  dishonest,  he  will  lie  as  to  conditions; 
if  he  does  not  understand  the  work,  he  will  increase  costs  and 
reduce  the  efficiency  of  the  campaign.  It  is  imperative  to  get 
good  men  for  this  work.  Such  men  as  described  are  not  picked 
up  everywhere.  Generally,  the  writer  has  had  to  train  his  own 
men;  but  it  is  essential  that  they  be  made  of  the  right  material. 

LePrince1  says: 

"The  success  of  the  work  will  depend  very  largely  on  the  ability  and 
personal  interest  taken  in  the  work  by  the  inspector  or  foreman  in 
charge  of  the  oiling  and  the  oiling  squad.  There  must  be  one  reliable 
and  active  person  held  responsible  for  the  efficienc}'  of  the  field  work. 
He  must  go  to  all  possible  production  areas  at  frequent  intervals  and  see 
and  know  that  the  work  is  being  satisfactorily  performed,  that  no  known 
places  are  missed,  that  no  mosquito  larvae  reach  the  pupal  stage  of 
development  and  that  places  needing  attention  are  promptly  attended 
to.  A  knowledge  of  the  local  conditions  of  topograph}7  and  possibilities 
of  water  being  retained  in  any  locality  during  unusually  wet  seasons 
is  essential.  When  the  pools,  ditches  and  stream-beds  become  drj', 
they  must  be  re-inspected  after  showers,  as  some  of  them  may  retain 
water  in  pools  and  need  attention.  This  frequently  happens  in  out-of- 
the-way  places.  The  inspector  must  never  assume  that  everything  is 
in  a  satisfactory  condition,  but  must  go  and  see  and  be  certain  of  it." 

In  regard  to  laborers,  LePrince  adds : 

1  "Control  of   Malaria:  Oiling  As  an   Anti-mosquito   Measure,"    U.   S. 
Public  Health  Service,  1915. 
6 


82  MOSQUITO  ERADICATION 

"In  all  mosquito  control  work,  it  is  economy  to  select  intelligent 
laborers,  who  take  an  interest  in  the  work,  and  to  pay  them  a  higher 
wage  as  they  become  skilled.  The  extra  pay  is  saved  many  times  over 
in  results  and  saving  of  material  as  compared  with  the  work  of  untrained 
labor.  The  man  who  notes  at  a  glance  whether  oil-drips  he  sees  are 
working  properly  and  goes  out  of  his  way  to  remove  an  obstruction  in 
a  stream,  because  he  knows  it  may  save  extensive  re-grading,  and  attends 
to  other  apparently  trivial  but  important  details,  is  worth  two  ordinary 
laborers.  Incompetent  laborers  are  apt  to  increase  operating  expenses, 
and  are  careless  about  using  oil  properly.  The  work  to  be  done  may 
be  scattered  over  a  relatively  large  area,  and  the  inspector  cannot  watch 
the  men  closely.  His  work  is  of  such  a  character  that  he  must  often 
leave  his  laborers  and  devote  his  time  to  inspection." 

MATERIALS  AND  EQUIPMENT 

As  soon  as  it  is  definitely  known  that  a  campaign  is  to  be  put 
on  in  any  community,  the  director  should  immediately  take  steps 
to  order  his  materials  and  equipment. 

Arrangements  should  at  once  be  made  for  an  adequate  supply 
of  oil.  Frequently  this  may  be  obtained  from  local  concerns, 
such  as  railroads,  ice-plants,  oil  refineries,  pumping  plants, 
oil-wells,  oil  dealers  etc.  If  possible,  it  is  generally  preferable 
to  get  it  from  local  sources,  since  this  may  result  in  lower  charges 
for  freight  and  also  may  obviate  the  necessity  of  arranging  for 
storage.  If  obtained  locally,  it  usually  may  be  delivered  a  few 
barrels  at  a  time  as  needed.  Should  this  be  impossible,  however, 
or  should  very  large  quantities  be  needed,  it  probably  would  be 
preferable  to  buy  from  the  refinery  direct,  the  oil  to  be  shipped  in 
tank  or  carload  lots.  In  any  event,  a  definite  contract,  with 
optional  amounts  stated,  if  necessary,  should  be  entered  into, 
so  that  there  will  be  no  possibility  of  having  the  supply  give  out 
at  a  critical  time. 

Equipment  should  include  enough  sprayers  and  drip  cans  to 
handle  any  situation  that  may  develop.  The  sprayers  should 
be  ordered  early,  like  the  oil,  as  it  may  take  some  time  for  them 
to  reach  the  seat  of  the  campaign.  Enough  tools  should  also  be 
bought  locally  for  the  drainage  gang. 


CHAPTER  V 
ADMINISTRATIVE  ASPECTS  OF  THE  CAMPAIGN 

MOSQUITO-BREEDING  ABOUT  HOMES 

While  in  previous  chapters  something  has  been  said  of  the 
breeding  habits  of  the  various  species  of  common  American  mos- 
quitoes and  of  the  necessity  for  careful  inspection,  it  is  desired 
here  to  emphasize  the  fact  that,  in  the  average  inland  town,  the 
people  themselves  raise  most  of  the  mosquitoes  that  afflict  them. 

It  has  been  the  writer's  observation  that  it  is  a  comparatively 
simple  matter  to  eradicate  Anopheles  mosquitoes,  which,  as  has 
already  been  pointed  out,  breed  mostly  in  ditches,  pools  and 
other  natural  breeding  places.  But  when  it  comes  to  eliminating 
breeding  of  house  mosquitoes,  the  director  of  the  campaign  has 
a  man's  job  on  his  hands. 

Yet,  even  though  the  campaign  is  primarily  a  health  measure- 
that  is,  directed  in  the  first  instance  against  malaria-bearing 
mosquitoes — it  must  nevertheless  include  suppression  of  all 
mosquitoes  to  be  considered  a  success  by  the  people  who  put  up 
the  money.  The  average  person  regards  mosquitoes  as  mos- 
quitoes, and  he  would  be  very  apt  to  consider  as  "phony"  any 
malaria  reduction  figures  if  he  did  not  notice  a  corresponding 
abatement  in  the  numbers  of  house  mosquitoes. 

Yet  these  average  persons  are,  as  intimated  above,  frequently 
responsible  for  the  presence  in  the  community  of  more  mosquitoes 
than  all  the  pools,  ditches,  swamps  and  streams  in  flight  distance. 

The  writer  has  repeatedly  found  homes  in  which  mosquitoes 
were  breeding  abundantly  in  10  to  20  different  breeding-places. 
There  would  be  a  number  of  tin  cans  containing  water  scattered 
about  different  parts  of  the  yard;  a  rain-water  barrel  or  two; 
a  non-mosquito-proof  cistern;  a  couple  of  pools  under  the  house 
caused  by  leaky  pipes  or  drip  from  the  ice-box;  an  uncovered 
cess-pool;  a  water-trough  for  stock;  and,  perhaps,  stopped-up 
roof  gutters.  And  these  cases  were  not  in  the  slums  or  the  negro 
quarter;  on  the  contrary,  they  were  often  at  the  homes  of  the 
leading  people  of  the  community. 

The   writer   once   received   a   complaint  from   the   wealthiest 

83 


84 


MOSQUITO  ERADICATION 


woman  in  town.     She  had  been  one  of  the  principal  factors  in 
raising  money  for  the  campaign  and  had  taken  great  pains,  as 


(Photo  by  E.  H.  Magoon,  C.  E.) 
Fig.   54. — View   of   a   home-yard   in   which   21    potential    breeding   places   were 
found,  17  of  them  actually  containing  larvae. 

she  thought,  to  keep  her  home  in  shape.  Yet,  upon  brief 
investigation,  he  found  mosquitoes  breeding  abundantly  in  five 
different   breeding   places — the   cellar,    which   had   partly   filled 


(Photos  by  E.  H.  Magoon,  C.  E.) 
Fig.  55.  Fig.  56.  Fig.  57. 

Fig.   55. — Inspector  finds  larvae  in  the  inevitable  rain-water  barrel  at  the 
home  of  a  southern  darky. 

Fig.  56. — He  prevails  upon  the  lady  of  the  house  to  pour  some  kerosene  into 
the  barrel  to  kill  the  larvae. 

Fig.  57. — And  to  keep  the  barrel  covered  thereafter,  so  that  mosquitoes  can- 
not lay  any  more  eggs  in  it. 

with  water  after  a  heavy  rain,  a  large  private  swimming-pool, 
an  old,  forgotten,  defectively-covered  cess-pool,  a  choked-up 
roof  gutter  and  an  old  well,  not  then  in  use. 


ADMINISTRATIVE  ASPECTS  OF  THE  CAMPAIGN 


85 


In  many  Southern  towns,  parts  of  the  negro  districts  are  not 
supplied  with  city  water.  In  these  cases,  the  negroes  either 
have  shallow  wells  or  else  haul  water  for  drinking  purposes, 
which  is  generally  kept  in  barrels.  Each  of  these  conditions 
give  rise  to  a  problem  of  considerable  magnitude. 

PLANNING  THE  INSPECTION  SYSTEM 

The  only  way  in  which  the  conditions  above-mentioned  can  be 
overcome  is  by  means  of  a  rigorous  system  of  inspection  of 


Fig.  58. — Septic  tank  with  screening  rotted  away — an  ideal  breeding  place  for 

Culex  pipiens. 


premises.  This  should  be  coupled  up  with  the  inspection  of 
streams,  marshes,  etc.,  in  the  outlying  area  in  such  manner  that 
every  spot  in  which  breeding  may,  by  any  possibility,  take  place 
be  visited  once  a  week  or  once  every  10  days  at  most. 

In  planning  the  inspection  work,  the  community,  if  large, 
should  be  divided  up  into  inspection  areas,  with  an  inspector  in 
charge  of  each.  If  the  town  is  small,  perhaps  one  inspector 
can  handle  it.  It  has  been  the  writer's  experience  that  one 
inspector,  doing  nothing  else,  should  be  able  to  handle  from  30 
to  50  average  residential  blocks,  covering  the  whole  area  thor- 
oughly once  a  week  or  once  every  10  days.  Inspection  of  the 
outlying  area — pools,  streams,  ponds,  etc.  does  not  take  nearly 
so  long  comparatively  as  inspection  of  premises. 


86 


MOSQUITO  ERADICATION 


The  inspector  should  be  equipped  with  a  long-handled  dipper, 
preferably  of  white  enamel,  and  a  small  hand  mirror,  to  facilitate 
finding  larvae.  The  dipper  is  used  to  dip  up  water  from  pools, 
barrels,  etc.,  for  closer  scrutiny.  The  mirror  is  used  to  reflect 
sunlight  upon  the  surface  of  the  water,  so  that  larvae  may  be 
easily  spotted  whether  at  the  surface  or  in  the  depths.  According 
to  Parham,1  it  was  found  that  one  inspector,  equipped  with 


(Photo  by  E.  H.  Magoon,  C.  E). 
Fig.   59. — Inspector  looking  over  tub  of  old  bottles  and  tin  cans  for  mosquito- 
breeding. 


dipper  and  mirror,  could  cover  territory  requiring  four  inspectors 
not  so  equipped. 

In  dealing  with  conditions  found  by  the  inspectors,  the 
following  procedure  has  been  found  effective: 

On  his  first  covering  of  his  beat,  the  inspector  should  take  his 
time.  He  should  explain  his  mission  to  the  occupants  of  the 
houses  he  visits,  point  out  any  actual  or  potential  breeding 
places,  insist  politely  that  they  be  done  away  with  immediately 
and  leave  an  anti-mosquito  leaflet.2     If  he  sees  any  condition 

1  Naval  Medical  Bulletin,  vol.  15,  No.  2,  April,  1921. 

2  A  suggested  anti-mosquito  leaflet  is  printed  as  Appendix  C. 


ADMINISTRATIVE  ASPECTS  OF  THE  CAMPAIGN  87 

that  he  considers  should  be  handled  by  the  anti-mosquito  forces, 
such  as  a  big  pool  in  a  street  ditch  that  needs  draining,  emergency 
oiling  to  prevent  early  hatching  of  a  large  number  of  pupae, 
etc.,  he  should  make  a  note  of  it  and,  on  arriving  at  the  office, 
should  transcribe  these  notes  on  appropriate  slips  of  paper  made 
out  somewhat  as  follows: 

FORM  NO.  5 

Work  Order 

Date 

To Foreman 

Location 

Work  needed 

Inspector 


The  work  described  above  has. 


Date 

Foreman 

These  work  orders  are  then  gone  over  by  the  director  and 
turned  over  to  the  appropriate  foreman,  be  it  oiling,  fish  control, 
drainage  or  maintenance.  The  foreman  to  whom  it  is  turned 
over  performs  the  work,  if  the  situation  requires  it,  in  any 
case  making  a  report  on  the  matter  in  the  space  left  for  that 
purpose. 

Should  such  action  be  desirable,  the  inspector  may  take  a 
malaria  census,  as  described  in  Chapter  IV,  while  covering  his 
beat  for  the  first  time.  While  it  would  require  some  extra  time 
to  do  this,  the  valuable  information  gained  probably  would  be 
worth  it. 

HANDLING  THE  NEGLIGENT  CITIZEN 

On  his  second  trip  of  inspection,  the  inspector,  wherever  he 
finds  breeding  going  on  through  fault  of  the  occupant;  of  the 
premises,  should  leave  a  formal  notice.  A  form  more  or  less 
similar  to  the  following  has  been  used  successfully  by  the  writer: 


88  MOSQUITO  ERADICATION 

FORM  NO.  6 

CITY  OF 

OFFICIAL  NOTICE 

192 


To. 


You  are  herewith  notified  that  a  mosquito  breeding-place  exists  on  your 

premises Street,  in  violation  of  the  City  Ordinances. 

This  mosquito  breeding-place  is  a 

You  are  respectfully  advised  that  you  have  three  days  in  which  to  abate 
the  mosquito  breeding-place  above  mentioned.  Failure  to  do  so  within  the 
three  days  will  render  you  liable  to  a  fine  of  from  $1  to  $25  and  costs. 

Each  day  that  the  breeding-place  exists,  after  the  three  days  mentioned, 
constitutes  a  separate  offense,  under  the  City  Ordinances. 


Director,  City 
Anti-Mosquito  Campaign. 


The  above  form  is  the  formal  notice  required  by  the  ordinance 
before  prosecution  may  be  initiated.  At  the  end  of  the  3  days, 
the  inspector  should  return  to  the  offender's  home.  If  the  work 
has  not  been  done,  he  should  consult  immediately  with  the 
director  of  the  campaign  with   a  view  to  laying  a  complaint. 

If  a  charge  is  laid,  it  is  necessary  that  the  inspector  be  on 
hand  at  the  proper  time  to  testify.  Until  he  knows  his  inspectors 
thoroughly,  it  is  expedient  that  the  director  himself  view  the 
spot  to  make  sure  that  the  situation  falls  within  the  scope  of 
the  ordinance,  that  the  inspector  has  given  the  notice  and  that  the 
demand  made  is  not  unreasonable,  as,  for  example,  suggesting 
expensive  drainage  work  when  the  situation  can  just  as  well  be 
handled  by  inexpensive  fish  control. 

Streams,  ponds,  ditches,  pools,  etc.,  which  the  anti-mosquito 
forces  are  oiling  or  otherwise  working  should,  of  course,  also  be 
carefully  inspected  weekly  and,  should  any  breeding  be  found, 
the  inspector  should  at  once  report  it  to  the  director  for  appro- 
priate action.  This  has  a  tendency  to  keep  the  workers  on  the 
alert. 

COMPLAINT  BUREAU 

While  engaged  in  co-operative  malaria  eradication  demon- 
stration work  in  Texas,  the  writer  tried  out  the  idea  of  opening 
a  complaint  bureau.     It  was  considered  that  this  would  afford 


ADMINISTRATIVE  ASPECTS  OF  THE  CAMPAIGN 


89 


a  good  clue  to  areas  in  which  breeding  might  be  taking  place 
unknown  to  the  anti-malaria  personnel.  It  was  also  believed 
that  the  knowledge  that  poor  work  would  soon  be  revealed  to 


|pr"  ' 

^SH 

.'■-.'"  6 

.  "~«  . 

■■to*  ' 

■^  ^Tn  -Mtf 

R^kMs 

(Pftoto  6{/  £.  tf.  Magoon,  C.  E.) 
Fig.  60. — Surface  cisterns  placarded  by  inspector.     Such  cisterns  make  ideal 
breeding-places,   when,     as     is     usually     the     case,     they     are     not     mosquito- 
tight. 

the  director  by  sufferers  therefrom  might  stimulate  the  inspection 
staff.     Both  of  these  beliefs  materialized. 

The  system  followed  was  repeatedly  to  outline  the  plan  through 
the   newspapers,    requesting   all   residents   suffering   from    mos- 


(Photo  by  E.  II.  Mogoon,  C.  E.) 
Fig.   01. — Inspector  dipping  for  larvae  in  a  borrow-pit. 

quitoes  to  any  considerable  extent  to  file  complaints,  either  by 
telephone  or  personally  with  the  anti-malaria  office,  but  not 
until  each  complainant  had  first  thoroughly  inspected  his  own 
premises. 


90  MOSQUITO  ERADICATION 

A  number  of  blanks  were  printed  on  which  to  take  down  the 
complaints.     These  blanks  were  somewhat  as  follows: 

FORM  NO.  7 
Complaint 


Date 

Complainant 

Address 

Suspected  Source  of  Breeding 

Found 


Address 

Action  Taken. 


Date  Inspector 

As  indicated  by  the  form,  these  complaint  cards  were  turned 
over  by  the  director  to  the  appropriate  inspector,  who  then 
investigated  the  complaint  and  reported  back  what  he  had  found 
and  what  action  he  had  taken. 

On  the  whole,  the  writer  was  very  well  satisfied  with  the 
operation  of  the  complaint  bureau.  It  unquestionably  had  a 
good  effect  in  revealing  breeding-places  that  the  anti-malaria 
forces  were  not  aware  of  and  also  in  stimulating  the  inspectors. 
It  also  helped  convince  the  people  that  sincere  and  conscientious 
efforts  were  being  made  to  keep  down  domestic  mosquitoes  and, 
at  the  same  time,  did  much  to  teach  them  to  keep  their  premises 
in  shape,  since,  in  a  very  high  proportion  of  the  cases,  the  com- 
plainant himself  was  found  to  be  raising  the  mosquitoes. 

One  slight  disadvantage  was  that  people  occasionally  would 
make  complaints  for  which  no  basis  could  be  found — that  is, 
no  breeding  places  could  be  located  in  the  vicinity  and  neighbors 
would  report  that  thejr  had  noticed  no  mosquitoes.  In  such 
cases,  the  time  spent  in  trying  to  trace  down  the  supposed 
breeding-places  was  wasted.  Another  disadvantage  of  the  plan 
was  that  it  led  people  to  expect  too  much;  often,  they  would  file 
a  complaint  on  the  strength  of  having  noticed  only  a  single 
mosquito. 


ADMINISTRATIVE  ASPECTS  OF  THE  CAMPAIGN 


91 


PUBLICITY 

Properly  got-out  publicity  is  probably  one  of  the  greatest 
helps  the  director  of  an  anti-mosquito  campaign  can  have.  If 
must  be  remembered  that,  in  its  larger  aspects,  the  whole  work 
is  more  than  anything  else  an  educational  endeavor.  If  this 
be  true,  the  educational  end  of  it  is  really  more  important  than 
the  reduction  of  mosquitoes  and  should,  accordingly,  be  given 
the  attention  it  merits.  Even  on  selfish  grounds,  the  people 
should  be  taught  to  protect  themselves  since,  in  this  way,  the 
work  of  the  director  and  the  expenses  of  the  campaign  are 
correspondingly  decreased. 


(Photo  by  E.  H.  Mogoon,  C.  E.) 
Fig.  62. — Top  of    underground  cistern,  in  which  breeding  was  very  abundant 
until  a  few  Gambusia  were  put  in  it. 

In  much  anti-mosquito  work,  it  is  customary  to  cease  publicity 
activities,  once  the  funds  have  been  raised,  but  this  is  a  mistake. 
The  publicity  designed  to  get  the  money  should  be  but  the 
beginning. 

It  has  been  the  practice  of  the  writer  to  keep  up  a  steady  flow 
of  publicity  from  the  time  the  work  is  first  broached  to  and 
beyond  the  end  of  the  campaign.  Thus,  as  soon  as  it  was  defi- 
nitely decided  that  the  campaign  was  to  be  put  on  in  a  town,  he 
would  explain  the  scientific  facts  upon  which  the  work  is  based, 
refer  to  the  great  success  of  similar  work  in  Cuba,  Panama  and 
elsewhere  and  then  recount  the  local  problems  and  the  methods 
to  be  used  in  handling  them. 

Then,  as  the  work  progressed,  he  would  issue  statements  as  to 
the  progress  being  ^rnade,  the  percentage  of  drainage  completed, 
the  formation  of  an  oiling  gang,  its  mode  of  functioning,  the 


92  MOSQUITO  ERADICATION 

appointment  of  inspectors,  their  duties,  habits  of  Gambusia 
(the  anti-mosquito  fish),  establishment  of  aquaria,  stocking  of 
streams  and  ponds,  etc. 

Accounts  of  prosecutions  should  be  brief,  but  complete,  with 
no  comment. 

TEXTS  FOR  ARTICLES 

Texts  for  articles  from  time  to  time  may  be  found  in  discoveries 
of  unusual  breeding-places,  decrease  in  incidence  of  mosquito- 
borne  diseases  as  reported  by  the  physicians,  compared  with 
previous  years,  statements  by  prominent  local  persons  as  to  the 
reduction  of  mosquitoes,  comments  by  traveling  men  as  to 
conditions  compared  with  other  towns,  visits  by  health  officials, 
etc. 

The  writer  used  to  make  a  practice  of  issuing  a  statement 
immediately  after  every  heavy  rain,  advising  citizens  to  look  over 
their  premises,  dump  the  water  out  of  any  collections  of  tin  cans, 
inspect  their  roof  gutters,  screen  their  rain-water  barrels  and 
cisterns,  etc.  The  articles  would  be  arranged  a  little  differently 
each   time,   but  the   substance   would   be   virtually  the   same. 

Editors  of  the  various  newspapers  are  almost  invariably 
genuinely  willing  to  co-operate  in  this  way,  taking  the  view  that 
the  work  is  a  public  benefit  for  the  town  and  worthy  of  being 
"boosted." 

A  few  points,  however,  should  be  borne  in  mind  in  dealing 
with  the  editors.  They  are  usually  busy  men  and  have  little 
or  no  time  for  long-drawn-out  conversations.  When  the  director 
has  occasion  to  consult  with  them,  he  should  be  brief  and  to  the 
point.  For  the  same  reason,  the  director  will  stand  a  much 
better  chance  of  getting  his  publicity  matter  "over,"  if  he  will 
write  it  out  himself,  than  if  he  asks  the  editor  to  write  it. 

In  form,  the  articles  should  be  short  and  snappy.  Rarely 
should  an  article  reach  half  a  column  in  length.  Generally,  they 
should  not  run  more  than  a  quarter  of  a  column.  Nor  should 
they  have  long,  involved  preambles.  The  very  first  sentence 
should  uncover  the  root  of  the  whole  business.  Long,  technical 
words  should  be  avoided.  Write  the  article  "as  though  you 
were  telling  it  to  the  policeman." 

Another  important  point  to  be  remembered  is  that  the  articles 
must  contain  no  disagreeable  references  to  any  person.  No 
comment  should  be  made  in  regard  to  any  one.     Nothing  will 


ADMINISTRATIVE  ASPECTS  OF   THE  CAMPAIGN         93 

get  one  "in  wrong"  with  an  editor  quicker  than  ill-considered 
references  to  local  persons  or  institutions. 

OTHER  METHODS  OF  OBTAINING  CO-OPERATION 

Other  methods  of  obtaining  the  co-operation  of  the  public  in 
eradicating  mosquito-breeding  are  summarized  by  LePrince1  as 
follows : 

1.  "Short  talks,  direct  to  school  children,  showing  them  how  mos- 
quitoes are  produced  in  water-containers  and  asking  them  to  inspect 
the  back-yards  every  Saturday  morning  and  empty  or  oil  stagnant 
water. 

2.  "At  West  Point,  Miss.,  the  Mayor  sounded  the  fire  siren  every 
Saturday  morning  at  9  o'clock  as  notice  to  the  town  folks  to  go  out  into 
the  house-yards  and  eliminate  containers  breeding  mosquitoes  and  also 
to  put  a  little  kerosene  into  the  closet  and  flush  it  to  get  a  good  oiling  of 
the  Culex  pipiens  producing  sewer  ditch. 

3.  "At  Bastrop,  the  children  in  the  school  were  asked  to  look  after 
their  own  back-yards.  At  the  end  of  the  season,  the  teachers  asked 
each  child  what  he  or  she  had  done,  and  about  92  per  cent  had  helped 
in  the  campaign. 

4.  "A  composition  by  each  pupil  on  the  way  to  eliminate  mosquitoes, 
with  the  best  ones  published  in  the  local  press  and  one  or  two  small 
prizes  offered  by  Chambers  of  Commerce  for  the  boys  and  by  women's 
clubs  for  girls  will  help.  Don't  forget  to  advertise  the  progress  in  the 
local  paper. 

5.  "The  motion  picture  houses  are  generally  willing  to  show  notices  to 
the  public  without  cost,  and  a  few  new  ones  each  month  will  keep  up 
interest  in  the  work.  Radio  mat  slides  are  used  in  preparing  these 
notices,  and  cost  about  $3.00  per  50." 

DAILY  REPORTS 

A  complete  record  of  every  activity  of  the  anti-mosquito  Ibices 
should  be  kept,  together  with  full  cost  data  as  to  the  different 
kinds  of  work.  These  records  should  be  kept,  not  only  to  account 
for  the  money  spent,  but  also  to  form  a  basis  for  estimates  for 
work  in  future  years  or  in  other  places. 

Each  foreman  should  be  required  to  submit  a  daily  report  of 

1  Circular  No.  10,  Office  of  Malaria  Investigations,  U.  S.  Public  Health 
Service,  April  6,  1920. 


94 


MOSQUITO  ERADICATION 


his  work.  The  experience  of  the  writer  has  been  that  it  is 
impossible  for  the  majority  of  foremen  properly  to  fill  out  a 
report  form  that  is  at  all  complex.  With  the  average  foreman, 
about  all  that  can  be  expected  is  a  record  of  the  number  of  men 
he  has  and  the  amount  of  their  time,  together  with  a  short 
statement  of  the  work  accomplished,  and  even  these  simple 
data  will  have  to  be  carefully  checked. 

The  following  form,  and  slight  modifications  of  it,  have  been 
used  by  the  writer  for  several  years  for  all  kinds  of  mosquito 
eradication  work: 

FORM  NO.  8 


.  Foreman 
Time  Summary 


Date 


No. 

Classification 

Hours 
worked 

Hourly 
rate 

Amount 

Remarks 

Foren 
Labor 

lan. . 

er.  . 

Team 
Drive 

or  truck . . 

r. . 

Work  Summary 

Kind  of  work 

Where 

Lineal  feet 
done 

Square  feet 
done 

,     ,         Gallons 
stocked          .,         , 
...    _  ,        oil  used 
with  fish  j 



Foreman 
The  inspectors  also  should  make  out  a  general  report  daily, 


ADMINISTRATIVE  ASPECTS  OF  THE  CAMPAIGN         95 

in  addition  to  the  notices,  etc.,  mentioned  in  an  earlier  part  of 
this  chapter.  A  form,  more  or  less  similar  to  the  following,  is 
suggested : 

FORM  NO.  9 

Inspector's  Daily  Report 

Date 


Number  of  houses  inspected  this  date 

Number  of  houses  found  raising  mosquitoes 

Kinds  of  mosquitoes 

Other  places  inspected 

Other  places  breeding  mosquitoes 

Kinds  of  mosquitoes 

Number  of  official  notices  issued 

Number  of  prosecutions  attended 

Number  of  work  orders  issued 

Remarks 


Inspector 

These  reports  will  provide  some  interesting  information  as  to 
the  progress  of  the  citizens  in  keeping  their  homes  in  shape. 
After  the  campaign  has  been  in  progress  for  a  few  months,  it 
will  be  found  almost  invariably  that,  as  a  result  of  the  educational 
work,  the  ratio  of  houses  visited  to  houses  found  raising  mosqui- 
toes will  show  a  great  improvement. 

RECORDS 

There  should,  of  course,  be  a  complete  record  of  expenditures 
of  all  kinds,  and  entries  in  this  should  be  made  immediately  the 
expenditure  is  made  or  authorized.  This  record  should  prefer- 
ably be  of  such  form  that  the  kind  of  work  to  which  the  expendi- 
ture is  to  be  charged  is  clearly  apparent. 

The  following  form  was  used  by  the  writer  for  several  years. 
It  may  be  modified  to  suit  the  occasion : 


90 


MOSQUITO  ERADICATION 

FORM  NO.  10 
Expenditures  Record 

Ending . 


Payee 

For 

what 

Order 
No. 

Amount 

Date  ap- 
proved 

Date 
paid 

Charge 
to 

Re- 
marks 

In  case  any  of  the  bills,  payrolls  or  other  entries  should  include 
sums  chargeable  to  two  or  more  different  things,  such  as  a  com- 
bined drainage  and  inspection  payroll  or  a  bill  for  equipment  for 
both  oiling  and  fish-control  work,  such  sum  should  be  appro- 
priately divided  between  the  two  kinds  of  work  and  explanation 
made  under  the  heading  of  "Remarks." 

Taking  the  sums  expended  from  the  expenditures  record  and 
the  quantities  of  work  done  from  the  daily  reports  of  the  foremen 
or  other  sources,  the  director  is  then  able  to  assemble  his  cost 
data  for  the  different  kinds  of  work.  Thus,  at  any  time,  he  can 
add  together  his  expenditures  on  drainage  work — payrolls  and 
material — as  recorded  in  the  expenditures  record,  add  up  his 
figures  of  work  accomplished  from  the  drainage  foreman's  daily 
reports  (or,  better  yet,  accurately  measure  the  work  done)  and 
learn  just  what  his  drainage  is  costing  him  per  lineal  foot  or  other 
unit.  The  same  can  be  done  with  maintenance,  oiling,  fish- 
control,  individual  jobs,  etc. 

On  work  with  which  the  writer  has  been  associated,  it  has 
usually  been  customary  to  do  this  work  every  month,  as  a  basis 
for  the  monthly  reports  required. 

It  is  suggested  that  separate  records  of  this  kind  be  kept  for 
the  following  activities: 

Activity  Charges  to  be  Included 

Supervision Salaries  of  director  and  clerical  help,  if  any; 

transportation  of  director. 

Inspection Salaries  of  inspectors;  transportation,  if  any. 

Drainage Payrolls  of  laborers  and  foremen;  materials. 

Maintenance  of  drainage Labor  payrolls. 

Oiling Cost  of  oil;  transportation;  labor  payrolls. 

Fish-control Labor  payrolls;  transportation. 

Miscellaneous Equipment  and  other  miscellaneous  expenses 


ADMINISTRATIVE  ASPECTS  OF  THE  CAMPAIGN         97 

The  records  of  malaria  calls  made  by  physicians,  described  in 
Chapter  IV,  should  also  be  gone  over  carefully  each  month,  and 
any  physicians  delinquent  in  reporting  should  be  seen  without 
delay,  since  it  is  imperative,  for  effective  comparison  that 
complete  and  accurate  figures  be  obtained. 

MAPS 

As  stated  in  an  earlier  chapter  a  map  of  the  community  in 
which  the  work  is  to  be  undertaken  should  be  obtained  and,  if 
practicable,  several  copies  should  be  made  of  it.  A  scale  of  1 
inch  to  200  feet  or  1  inch  to  400  feet  is  recommended. 


(Photo  by  E.  H.  Magoon,  C.  E.) 
Fig.   63. — Mosquitoes  were  breeding  abundantly  in  a  little  water  in  the    old 
kettle  clinging  to  the  bank.     There  was  no  breeding  in  the  stream  itself,  how- 
ever, owing  to  the  activities  of  larva-destroying  fish. 

On  one  copy  of  this  map,  there  should  be  marked  all  the  topo- 
graphical features  of  the  community  bearing  on  mosquito  produc- 
tion, as  found  during  the  survey.  As  old  ditches  and  channels 
are  cleared  (re-channeled),  as  new  ditches  are  completed,  as 
marshes  are  drained,  as  holes  are  filled  up,  as  ponds,  culverts, 
streams,  etc.,  are  stocked  with  fish,  as  oil  stations  are  organized, 
they  should  be  indicated  on  the  map  in  an  appropriate  manner, 
either  by  the  use  of  symbols  or  otherwise. 

7 


98  MOSQUITO  ERADICATION 

One  complete  copy  of  the  map  should  be  kept  in  the  office  of 
the  director  for  reference.  One,  on  which  places  that  require 
oiling  and  oil  stations,  etc.,  are  indicated,  should  be  given  the 
oiling  foreman  to  assist  in  working  out  an  oiling  schedule. 
Another,  showing  places  that  may  profitably  be  stocked  with 
fish,  such  as  pools,  streams,  swamps,  etc.,  should  be  given  the 
fish-control  foreman.  Another,  showing  the  ditches,  etc.,  should 
be  given  to  the  ditch  maintenance  foreman.  Each  inspector 
also  should  be  provided  with  a  copy  of  the  map,  with  each 
one's  precinct  indicated  thereon. 


CHAPTER  VI 
INLAND  DRAINAGE 

IMPORTANCE  OF  DRAINAGE  AS  AN  ANTI-MOSQUITO   MEASURE 

Drainage  is  one  of  the  most  reliable  and  permanent  methods  of 
mosquito  control.  Where  there  is  no  water  in  which  the  mos- 
quito eggs  may  develop,  there  can  be  no  mosquitoes,  and  when 
once  a  place  is  properly  drained,  it  should  remain  in  good  shape 
for  a  considerable  period,  with  a  certain  amount  of  maintenance. 
Unless  the  anti-mosquito  work  is  a  mere  temporary  expedient, 
therefore,  drainage  will  play  a  large  part  in  it. 

The  term  "drainage,"  however,  as  applied  to  anti-mosquito 
work,  signifies  a  procedure  somewhat  different,  as  a  rule,  from 
drainage  for  agricultural  and  other  purposes.  Such  drainage 
work,  as  a  matter  of  fact,  sometimes  produces  mosquito  breeding- 
places.  For  mosquito  eradication,  the  land  must  not  only  be 
properly  drained,  but  the  ditches  themselves  must  be  so  designed 
as  not  to  become  sources  of  breeding. 

Drainage,  as  an  anti-mosquito  measure,  may  include  any  or  all 
of  the  following,  and  maintenance  thereof:  Ditching,  open  and 
lined;  sub-surface  tile  drains;  vertical  drainage;  re-channeling 
of  natural  water-courses;  filling;  diking;  construction  of  tide-gates; 
pumping. 

The  last  three  will  be  considered  in  the  chapter  on  "Salt  Marsh 
Drainage,"  since  it  is  in  salt  marsh  work  that  they  are  generally 
employed. 

In  addition  to  being  a  most  effective  measure  by  itself,  drainage 
frequently  may  be  used  to  great  advantage  in  connection  with 
fish-control,  oiling  and  other  procedures.  Examples  of  such 
cases  are :  Construction  of  a  ditch  connecting  an  isolated,  Ashless 
pool  with  water  stocked  with  mosquito-destroying  fishes,  or  low- 
ering of  a  pond  to  reduce  the  area  that  requires  to  be  oiled. 

LIMITATIONS  OF  DRAINAGE 

While  drainage,  in  the  long  run,  probably  is  considerably 
cheaper  than  most  other  control  methods,  especially  oiling,  it 

99 


100  MOSQUITO  ERADICATION 

should  not  be  employed  without  discrimination.  There  is  no  use 
in  going  to  a  large  expense  in  draining  a  pond  that  can  be  con- 
trolled for  much  less  money  by  stocking  it  with  fish.  Nor  will 
it  pay  to  try  to  drain  a  swamp  that  can  be  protected  at  much  less 
expense  by  means  of  levees  or  dikes  and  tide-gates. 

On  the  other  hand,  drainage  has  many  advantages  in  addition 
to  its  value  as  an  anti-mosquito  measure.  Large  areas  of  swamp 
and  marsh  lands  have  been  rendered  cultivable  by  proper  drain- 
age.    Furthermore,  in  many  places  in  the  United  States  today, 


Fit;.   04. — Typical  anti-mosquito  ditching  location. 

the  land  is  not  producing  what  it  should,  because  it  is  not  drained. 
For  this  reason,  money  spent  on  anti-mosquito  drainage  fre- 
quently returns  a  double  profit — it  improves  the  health  of  the 
occupants  of  the  land  and  also  increases  the  productivity  of  the 
land. 

Again,  it  often  happens  that  the  cost  of  draining  swamp  land 
is  more  than  paid  for  by  the  natural  resources  thereby  rendered 
accessible.  Frequently,  the  lumber  alone  thus  made  available 
is  worth  more  than  what  the  drainage  cost. 

PRELIMINARY  WORK 

Whether  the  project  be  large  or  small,  it  generally  will  pay  to 
study  pretty  closely  the  topography  of  the  area.  If  the  project 
be  large  and  the  area  involved  be  low  and  flat,  sufficient  levels 
should  be  run  to  enable  a  contour  map  to  be  prepared;  the  main 
ditch  systems  should  be  laid  off  accurately  on  the  map  and  then  be 


INLAND  DRAINAGE 


101 


located  by  instrument  in  the  field,  stakes  being  set  at  50-  or 
100-foot  intervals,  with  the  cut  at  each  stake  marked  thereon. 

Even  if  the  project  is  not  large  enough  to  justify  this  amount  of 
preliminary  work — as  will  often  be  the  case — it  may  frequently 
be  necessary  in  low,  fiat  country  to  run  various  lines  of  levels  to 
ascertain  the  fall  available  and  the  best  location  for  the  main 
ditches. 

Where  the  country  is  hilly  or  rolling,  the  eye  alone  may  be 


Fig.   65. — A  common  type  of  anti-mosquito  ditch. 

sufficient  for  open-ditch  work,  although  in  all  cases  of  doubt,  the 
level  should  be  used. 

As  a  general  rule,  open  ditches  in  anti-mosquito  work  need  not 
be  graded  with  the  accuracy  of  a  sewer  trench,  though  there 
should  be  no  low  spots.  With  lined  ditches  and  sub-surface 
drains,  however,  this  is  not  the  case;  stakes  should  be  set  for 
these  in  all  cases. 

Owing  to  the  fact  that  mosquitoes  do  not  develop  in  standing 
water  for  several  days,  anti-mosquito  ditches  do  not  always  have 
to  be  as  large  as  ditches  for  agricultural  drainage  and  other 
purposes.     Thus,  if  a  ditch  will  carry  off  the  standing  water  in 


102 


MOSQUITO  ERADICATION 


4  to  6  days,  its  capacity  is  sufficient,  from  a  mosquito  control 
standpoint,  although  this  may  not  be  the  case  from  the  stand- 
point of  agricultural  drainage. 

TYPES  OF  INLAND  DRAINAGE  PROBLEMS 

Once  the  area  in  which  the  campaign  is  to  be  undertaken  has 
been  gone  over,  it  will  often  be  found  that  the  problems  to  be  met 
are  varied  and  numerous.     Some  breeding-places  may  be  handled 


(Photos  by  E.  B.  Johnson,  C.  E.) 

Fig.  66. — Left,  large  cat-tail  swamp  fed  by  a  spring;  right,  ditch  dug  to  lead 

water  around  the  swamp. 

best  by  means  of  fish-control;  others  best  by  oiling;  and  still 
others  best  by  drainage.  The  director  of  the  campaign  will  have 
to  study  each  problem  by  itself  and  decide  which  is  the  best 
method  of  dealing  with  it.  In  case  of  doubt,  the  method  that 
seems  cheapest  for  that  particular  problem  should  be  adopted. 
After  eliminating  those  places  in  which  fish-control  and  oil  may 
be  used  to  best  advantage,  a  considerable  number  of  places 
generally  will  be  left  that  obviously  require  drainage.  In  any 
large  project,  these  will,  as  a  rule,  be  of  several  different  types, 
and  hence  will  require  different  methods  of  treatment.  Among 
the  different  types  of  areas  requiring  drainage  may  be  the  follow- 
ing: Temporary  puddles,  stagnant  ditches,  blocked-up  streams, 
borrow-pits,  ponds,  lakes  and  swamps. 


INLAND  DRAINAGE 


103 


Hill 


Of  these,  the  first  three  usually  present  no  serious  problems, 
requiring  simply  open  ditching  or  re-channeling. 

Borrow-pits  should  be  treated  in  accordance  with  conditions. 
If  fairly  shallow  and  advantageously  located,  they  may  be 
ditched;  many  are  too  deep  for  other  than  vertical  drainage,  and 
may,  perhaps,  be  stocked  with  fish  or  oiled.  If  they  are  to  be 
drained  by  ditching,  the  procedure  is  generally  simple. 

"It  is  when  we  come  to  ponds,  lakes  and  swamps,"  says  Metz,1 
"that  the  real  problems  arise, 
and  it  is  best  perhaps  to  consi- 
der these  three  together.  Since 
the  difference  between  lakes  and 
ponds  is  only  one  of  degree,  and 
since  swamps  may  include  either 
or  both  of  the  other  two,  it  is  ob- 
vious that,  in  actual  practice, 
little  distinction  can  be  made  that 
would  involve  different  methods 
of  drainage.  It  is  more  impor- 
tant to  classify  such  areas  accord- 
ing to  the  sources  of  the  water, 
for,  in  this  case,  the  distinc- 
tions correlate  with  modes  of 
treatment. 

PROBLEMS    OF    POND,   LAKE 
AND  SWAMP  DRAINAGE 

"For  instance,  one  pond  or 
swamp  may  be  caused  by  the  ac- 
cumulation of  rain-water  and  may 
fluctuate  greatlv   with   the  sea-  V 

sons,  another  may  be  simply  a   F™.  67.-Seepag^ outcrop,  Case  No.  1. 

basin  in  the  channel  of  a  sluggish 

stream,  while  a  third  may  be  fed  from  springs  and  may  be  bordered  by 

a  seepage  outcrop. 

"In  the  first  of  these,  the  rain-water  swamp,  it  is  merely  necessary  to 
provide  a  small  channel  to  carry  off  the  surplus  water  left  after  the  main 
flood  waters  have  passed.     As  a  rule,  one  or  two  ditches  will  suffice. 

"In  the  second  case,  the  situation  is  more  difficult,  for  the  water 
supply  is  continuous  and  fluctuating.  The  swamp  will  vary  in  size 
with  high  and  low  water  in  the  stream,  and  a  drainage  operation  of 

1  "Some  Aspects  of  Malaria  Control  Through  Mosquito  Eradication," 
U.  S.  Public  Health  Service,  1919. 


104  MOSQUITO  ERADICATION 

considerable  magnitude  may  be  required  to  eliminate  it  .  .  .  In  case 
drainage  is  decided  upon,  it  will  probably  take  the  form  of  channeling 
the  stream  below  the  swamp  to  lower  the  water  and  increase  the 
flow.    .    .    . 

"The  third  case  mentioned — that  of  a  swamp  fed  by  a  seepage 
outcrop — presents  the  most  difficult  problem  of  all.  Here  we  have, 
not  only  an  area  of  standing  water,  probably  full  of  vegetation,  but  also 
a  series  of  tiny  puddles  in  the  form  of  hoof-prints,  etc.,  along  the  outcrop 
margin.  Each  of  these  is  a  potential  breeding-place  of  the  worst  kind. 
The  treatment  of  such  an  area  requires  a  special  procedure,  and,  since 
the  proposition  is  one  that  is  apt  to  be  found  in  most  any  locality,  it  may 
be  considered  in  some  detail. 

TREATMENT  OF  SEEPAGE  OUTCROPS 

"Seepage  water  usually  appears  on  the  hillsides,  etc.,  at  the  outcrop  of 
a  stratum  of  water-bearing  sand  or  gravel  underlain  by  an  impervious 
stratum  of  clay,  shale  or  other  material.  The  outcrop  may  be  in  the 
nature  of  more  or  less  distinct  springs  or  simply  a  gradual  oozing  out 
through  the  soil.  In  either  case,  it  is  fed  by  a  water-table  below  the 
surface,  and  treatment  must  be  aimed  particularly  at  this  water-table. 
It  does  not  suffice  to  dig  ditches  directly  away  from  the  springs  and  down 
the  hillside.  Such  a  method  would  require  a  separate  ditch  for  each 
spot  from  which  water  is  issuing,  and  would  mean,  in  many  cases,  a 
series  of  ditches  about  12  inches  apart  along  the  whole  hillside.  The 
only  effectual  way  of  collecting  the  water  in  such  places  is  by  means  of 
ditches  dug  at  right  angles  to  the  flow  of  the  seepage  water,  or,  in  other 
words,  across  the  exposed  end  of  the  water-table.  Such  ditches  may 
then  be  connected  to  one  or  more  main  ditches,  if  necessary,  and  the 
water  carried  down  the  hillside  parallel  to  the  seepage  flow.  These 
points  are  illustrated  roughly  in  the  accompanying  sketches  of  actual 
swamps. 

"In  No.  1,  there  was  a  seepage  on  both  sides  of  a  narrow  valley,  the 
water  coming  out  of  two  hills  opposite  one  another,  as  shown  in  the 
sketch.  As  a  result,  the  bottom  of  the  valley  in  this  region  was  a 
typical  cat-tail  swamp,  with  water  from  1  inch  to  2  feet  in  depth.  Since 
the  source  was  somewhat  up  on  the  hillside,  it  was  useless  to  dig  a 
ditch  through  the  bottom  of  the  swamp  and  down  the  valley.  This 
would  simply  carry  off  the  deep  water  and  leave  the  seepy  marsh  as  it  was. 
Instead,  a  deep,  narrow  ditch  was  dug  along  the  margin  of  each  hill, 
just  at  the  upper  edge  of  the  seepage  outcrop  and  at  right  angles  to  the 
flow  of  the  seepage  water.  In  this  manner,  the  water-table  was  inter- 
cepted, and  all  the  water  that  formerly  oozed  out  down  the  hillside  now 
seeps  into  the  ditch  and  is  carried  off.  As  a  result,  the  swamp,  no  longer 
fed  from  the  hillside,  has  dried  up. 


INLAND  DRAINAGE 


105 


DRYING  UP  A  SWAMP 

"In  case  No.  2,  a  more  complicated  situation  is  presented.  Here  the 
seepage  flow  is  from  a  large  U-shaped  bend  in  a  hillside,  resulting  in  a 
swamp  many  acres  in  extent,  with  a  small  lake  at  the  outer  edge.  The 
water-table  in  this  case  extended  clear  across  the  swamp,  but  was  con- 
cealed along  a  slight  elevation  running  down  the  middle.  On  account 
of  this  elevation,  it  was  necessary  to  drain  the  right  and  left  halves  of  the 
swampy  area  separately.     As  shown  in  the  sketch,  a  ditch  was  put 


HiM 

^tiZF'XJ*  ■"■■  -  ■  ^2'/>Hal 

^  Jfi?'-  V~f/.  :■ .  n.       .  .  • .  •  *-   '^%.J  ^ 


F1G    eg. — Seepage  outcrop,  Case  No.  2.      (A/«er  .1/V/z.) 

along  the  toe  of  the  hill  on  each  side  at  the  upper  margin  of  the  outcrop 
and  then  run  off  into  the  lake.  But  the  water-table  this  time  was  too 
deep  to  be  intercepted  entirely  by  one  ditch,  and  it  was  necessary  to  dig 
additional  intercepting  laterals  at  intervals  lower  down.  On  one  side, 
five  such  ditches,  more  or  less  parallel  to  one  another  and  at  right  angles 
to  the  seepage  flow,  were  required  to  catch  all  of  the  water  before  it 
came  to  the  surface. 

"In  case  No.  3,  an  outcrop  on  a  relatively  steep  hillside  is  represented. 
Here  it  was  necessary  to  dig  several  intercepting  laterals  parallel  to  one 
another  and  only  a  few  feet  apart  in  order  to  catch  all  of  the  flow. 
When  this  was  done  over  the  area  in  which  the  seepage  water  was  actu- 


106 


MOSQUITO  ERADICATION 


ally  coming  out  of  the  ground,  the  remainder  of  the  swamp  lower  down 
the  hillside  became  completely  dry. 

"In  each  of  these  cases,  collection  of  the  water  depended  upon  the 
ditches  being  constructed  primarily  as  intercepting  rather  than  con- 
ducting ditches.  In  the  case  of  swamp  No.  1,  the  ditches  happened  to 
be  intercepting  and  conducting  at  the  same  time;  but  more  often 
separate  conducting  ditches  must  be  constructed  to  carry  off  the  water 
after  it  has  collected  in  the  intercepting  ditches." 


>0r  •  jfcfr 


m*\  '/W,  !>W 


Fig.  69. — Seepage  outcrop,  Case  No.  3.     (After  Metz.) 


DITCH  CONSTRUCTION  IN  GENERAL 

The  open  ditch  is  the  type  of  ditching  most  frequently 
employed  in  anti-mosquito  drainage.  While  the  first  cost  is 
undoubtedly  less,  it  is  believed,  however,  that,  over  a  period 
of  years,  some  more  permanent  type  of  ditch  is  cheaper,  owing 
to  the  more  or  less  continuous  maintenance  expense  that  open 
ditches  require.  Open  ditches  must  be  kept  free  from  grass, 
weeds,  debris,  etc.,  and  the  scouring  action  of  the  water  in 
flood-times  must  also  be  repaired. 

Ditching  may  be  required  on  firm,  open  land,  where  the  expense 
is  at  a  minimum,  or  in  wooded  swamp  areas,  where  the  work 
becomes  costly  and  tedious.  The  methods,  of  course,  will  vary 
with  conditions;  thus,  on  firm  ground,  machinery  may  be  em- 
ployed to  great  advantage;  in  swamps,  dynamite  may  be  cheapest. 

In  all  cases,  however,  the  following  principles  are  applicable: 

1.  The  ditches  should  be  just  as  few  as  will  answer  the  purpose. 

2.  Wherever  possible,  they  should  have  clean-cut,  sloping- 
edges,  narrow  bottoms  and  straight  courses. 


INLAND  DRAINAGE  107 

To  comply  with  the  first  principle  mentioned,  the  main  ditch 
should,  in  all  cases,  be  constructed  first.  Frequently  it  will  be 
found  that  laterals,  which  appeared  to  be  needed  before  the  main 
ditch  was  dug,  will  not  be  required  at  all.  If  there  is  any  doubt 
as  to  the  need  for  a  lateral,  it  should  not  be  dug. 

In  regard  to  the  second  principle,  it  may  be  suggested  that,  in 
average  soils,  the  slopes  of  the  sides  of  the  ditches  should  be 
about  45  degrees;  in  sand  and  soft  mud,  the  slope  may  be  flatter, 
while,  in  hard  clay  and  rock,  it  may  be  almost  vertical.  The 
bottoms  should  be  made  narrow  so  that,  when  the  flow  is  small, 
the  water  will  have  no  opportunity  to  spread  out  and  form  pools. 
Straightness  of  course,  where  the  ditches  are  not  laid  out  by 
instrument,  may  be  attained  by  use  of  a  line,  where  necessary. 
Branch  ditches  should  join  main  ditches  at  acute  angles  or  curves, 
in  order  to  lessen  depositing  of  silt,  sand,  debris,  etc.,  at  the 
junction  point. 

HAND  DITCHING  ON  FIRM  GROUND 

Most  anti-mosquito  ditching  is  done  by  hand,  probably 
because  most  projects  are  too  small  to  justify  the  purchase  of 
machinery.  However,  when  machinery  is  available,  it  should 
be  used  wherever  practicable. 

The  chief  tools  needed  for  hand  ditching  are  picks  and  shovels. 
Where  the  earth  is  full  of  roots,  a  mattox  will  come  in  handy. 
A  tiling  spade  may  be  used  for  finishing  off  the  bottom.  Some- 
times a  hoe  will  prove  valuable.  The  phosphate  drag,  a  tool 
somewhat  resembling  a  potato-hook,  only  heavier,  is  useful 
for  cleaning  out  ditches  or  for  general  work  in  marshy  land  that 
is  full  of  roots. 

In  cutting  ordinary  ditches  by  hand,  no  great  technical  skill 
is  necessary.  Common  sense  and  ability  efficiently  to  handle 
men  are  the  chief  requisites.  Upon  beginning  work,  the  ditch 
should  be  laid  out  by  means  of  lines,  so  that  it  will  be  dug  straight. 
The  men  then  should  be  scattered  out  along  the  lines,  a  section 
being  allotted  to  each  team  of  two  men.  As  each  team  finishes 
its  section,  it  should  be  moved  forward  and  given  another  section. 

Constant  vigilance  is  essential  to  see  that  the  men  keep  the 
bottom  even — that  is,  avoid  alternate  humps  and  depressions. 
Probably  the  best  way  to  do  this  is  to  select  two  or  three  intelli- 
gent men  and  assign  them  the  job  of  finishing  the  bottom  of  the 
whole  ditch. 


108 


MOSQUITO  ERADICATION 


In  cases  where  no  instrument  is  available  for  checking  the 
accuracy  of  the  bottom-finishing,  water  may  be  admitted  to 


Fig.  70. 


(Photos  by  E.  B.  Johnson,  C.  E.) 
Above,  extensive  swamp;  below,  ditch  that  drained  it. 


the  ditch  at  its  upper  end  and  allowed  to  descend  to  the  lower 
end.  Presence  of  pools  will  indicate  a  ridge  or  a  depression,  as 
the  case  may  be,  and  enable  the  finishers  to  correct  their  errors. 


INLAND  DRAINAGE 


109 


(Photos  bu  E.  B.  Johnson,  C.  E .) 
FlG    7i._Above,  pond  caused  by  seepage  from  hill;  below,  ditch  at  base  of  hill, 
intercepting  seepage.     Shortly  after  the  ditch  was  completed  the  pond  dried  up. 


110 


MOSQUITO  ERADICATION 


If  no  water  is  available,  the  ditch  should  be  inspected  after  the 
first  shower,  and  any  corrections  that  may  be  needed  made  then. 

COST  OF  ORDINARY  HAND  DITCHING 

Anti-mosquito  ditching  is  generally  estimated  on  a  lineal 
foot,  rod  or  mile  basis,  instead  of  a  cubic  yard  basis.  Costs, 
of  course,  vary  materially  with  the  size  of  the  ditch,  the  nature 
of  the  soil,  the  rate  of  wages  paid  and  the  efficiency  of  labor. 
For  these  reasons,  it  is  impossible  to  give  any  exact  figures  as 
to  costs  of  hand  ditching. 

As  a  general  proposition,  it  may  be  said  that,  with  ordinary 
soil,  unskilled  labor  and  wages  from  $2  to  $3  a  day,  the  cost  of 
the  average  hand-dug  ditch  should  range  somewhere  between  2 
cents  and  5  cents  a  lineal  foot.  Swamp  work,  of  course,  will 
greatly  exceed  these  figures.  The  presence  of  large  numbers  of 
roots  and  stumps  also  will  increase  costs. 

The  following  figures  represent  approximate  hand-ditching 
costs  on  several  jobs  handled  by  the  writer  in  the  South,  the 
ditches  having  an  average  sectional  area  of  from  2  to  4  square 
feet  and  the  ditch  mileage  on  each  job  ranging  from  4  to  10 
miles: 


Project 

Wages 

Cost  per  lineal  foot 

No.  1 

No.  2                  

$3.00 
2.50 
2.50 
2.00 

0.056 
0.027 

No.  3                  

0.011 

No.  4              

0.023 

HAND  DITCHING  IN  SWAMPS 

Ditching  by  hand  in  real  swamp  areas  is  tedious  and  costly 
in  the  extreme.  Where  practicable,  the  ditches  should  be  laid 
out  with  lines  and  the  men  spread  out  as  already  described.  In 
some  cases,  however,  this  is  not  practicable. 

In  a  large  anti-mosquito  swamp  drainage  project  in  Georgia, 
with  which  the  writer  was  connected,  the  earth  was  so  soft  that 


INLAND  DRAINAGE  111 

pails  had  to  be  used  to  dump  it  out  with,  and  the  sides  of  the 
ditches  caved  in  as  soon  as  any  considerable  depth  was  reached. 
Laborers  sank  in  the  mud  up  to  their  hips.  In  order  to  make 
any  progress  at  all,  it  was  found  necessary  to  build  a  retaining 
wall  of  poles  on  either  side  of  the  proposed  ditch.  Even  then, 
much  of  the  mud  would  seep  back  into  the  ditch,  so  that  it  was 
found  practicable  to  excavate  only  a  few  inches  at  a  time.     The 


(Photos  by  E.  B.  Johnson,  C.  E.) 
Fig.   72. — Occasionally,   it  is  necessary  to   ditch  a  slough.      Here,  a  channel 
3    feet    deep    and    4    feet    wide    was    dug    through    the    lowest    part    of    the 
slough. 

ditch  would  then  be  left  to  dry  out  for  two  or  three  days,  when  a 
few  inches  more  would  be  dug.  This  kind  of  work  may  cost 
from  25  cents  to  $1.00  per  lineal  foot. 

Not  all  parts  of  a  swamp  will  be  as  bad  as  this,  of  course,  but, 
wherever  the  earth  is  soft  and  sloppy,  it  is  a  certainty  that  the 
costs  are  going  to  be  high.  Frequently,  it  is  also  difficult  to 
maintain  an  adequate  gang  of  laborers  under  such  conditions. 

While  costs  of  hand  ditching  in  swamps  will  vary  in  accordance 
with  circumstances,  it  is  believed  that  they  will,  on  the  average, 
run  several  times  as  high  as  costs  of  hand-ditching  on  firm  earth. 


112 


MOSQ  UI  TO  ERA  DICA  TION 


In  the  project  above-mentioned,  nearly  40  miles  of  ditches 
were  dug,  a  large  proportion  of  them  being  in  the  swamp  alluded 


Fig.  73. — Above, 
lagoon  completely 
cost  less  than  $50. 


(Photos  by  E.  B.  Johnson,  C.  E.) 
lagoon    that    was    a    bad   Anopheles  breeding-place;  below, 
dried     up.      This     was     accomplished     by     a     ditch     that 


to.     The  cost  averaged  $723.05  per  mile  or  13.7  cents  per  lineal 
foot. 


INLAND  DRAINAGE  113 

BLASTING  DITCHES  IN  SWAMPS 

A  cheaper  and  much  more  satisfactory  way  of  ditching  in 
swamp  areas  is  by  use  of  dynamite. 

There  are  two  distinct  methods  of  blasting  ditches — the  pro- 
pagated or  transmitted  and  the  electric.  The  propagated 
method  can  be  used  only  in  wet  soils,  while  the  electric  method 
can  be  used  in  fairly  dry,  as  well  as  wet  soils.  The  explosives 
and  blasting  supplies  needed  and  the  methods  of  loading  vary 
somewhat  in  the  two  methods. 

Propagated  firing  requires  only  the  explosive  itself  and  a  cap 
and  some  fuse  for  each  couple  of  hundred  feet  of  ditch,  while 
electric  firing  requires  wiring,  an  electric  blasting  cap  for  each 
charge  and  a  blasting  machine  or  other  source  of  current.  This 
advantage  of  the  former  method  is  sometimes  offset,  however, 
by  the  fact  that  it  requires  nearly  twice  as  many  holes  as  electric 
firing.  Theoretically,  both  methods  require  about  the  same 
amount  of  explosive;  in  practice,  however,  more  will  be  used  in 
transmitted  firing,  unless  the  work  is  done  very  skilfully.  The 
economy  of  this  method  comes  largely  from  a  saving  of  electric 
blasting  caps  and  time  and  the  need  for  little  equipment. 

MAKING  TRIAL  SHOTS 

In  blasting  ditches  by  the  propagated  method,  the  first  thing 
to  do  is  to  try  a  few  trial  shots  to  determine  the  best  depth  and 
spacing  for  the  holes.  For  ditches  up  to  3  to  3^  feet  deep, 
the  depth  of  the  holes  will  generally  be  from  24  to  30  inches  and 
the  spacing  between  holes  from  18  to  24  inches,  although  it  may 
be  necessary  to  change  these  figures  slightly.  If  water  covers 
the  cartridges  in  the  holes,  no  tamping  is  necessary;  otherwise 
the  cartridges  should  be  well  tamped  with  earth.  Eight  to  ten 
holes  should  thus  be  loaded  for  the  test  shots;  one  hole  should  be 
charged  with  an  extra  primer  cartridge,  and  it  is  also  well  to  put 
one  additional  in  each  hole  adjoining  the  primer. 

If  the  test  shot  makes  too  large  a  ditch,  the  spacing  may  be 
increased  a  little,  but  should  seldom  be  greater  than  24  inches 
and  then  only  in  warm  soil.  If  the  ditch  is  too  deep,  it  will  be  an 
indication  that  the  depth  of  holes  should  be  decreased. 

Small  ditches,  say  2  feet  deep  and  3  feet  wide,  may  be  excavated 
by  using  half  cartridge  charges,  but  in  such  case  the  spacing  be- 
tween holes  should  seldom  be  more  than  18  to  20  inches.     Larger 

8 


114 


MOSQUITO  ERADICATION 


ditches  may  be  obtained  by  using  two  or  more  cartridges  to  a  hole 
or  by  planting  a  second  row  of  cartridges  parallel  to  the  first.  In 
this  case,  one  electric  cap  should  be  used  in  each  row  of  holes 
or  else  an  extra  charge  or  two  should  be  put  in  between  the  rows 
to  insure  simultaneous  detonation  of  all  the  charges. 

After  the  test  shots  have  been  fired  and  the  proper  loading 
and  spacing  for  the  material  in  question  thus  determined,  the  line 
of  the  ditch  should  be  laid  out;  if  the  area  is  forested,  all  trees  of 


Loading  ^  Mow  out  a  stump 


-Fuse 


^-  Edge,      of    Proposed    Ditrfi 


■  /Paivi   of  dynamite 


-/PorVS  of  dynamite 


Edge    of  Proposed    Difch 


Lay -our  far  b/a sting  ditch,  hofes  6emq 
Spaced  /S"  to  24-" aoar-t  each 
yray. 

r  Edqe  of  proposed  ditrfi  ^ 

\  __~~^      Dynamite 


Section   of  Plant 


Attac/ting  cap  to  dynamite 
Fig.   74. — Sketches  showing  details  of  blasting  ditches  by  propagated  method. 

any  size  along  the  proposed  ditch  should  be  cut  down  and 
removed.  Then  one  man  should  make  the  holes  with  a  crowbar 
or  shovel  handle  and  a  second  should  insert  the  charges.  An 
extra  charge  or  two  should  be  planted  about  large  stumps,  logs, 
etc.  Ordinarily  lengths  of  from  150  to  200  feet  may  be  dis- 
charged at  a  time.  The  hole  midway  along  this  distance  should 
be  fitted  with  a  cap  and  fuse.  When  this  fuse  is  ignited,  the 
concussion  resulting  from  the  explosion  of  this  charge  explodes 
the  other  charges. 


INLAND  DRAINAGE 


115 


CLEANING  OUT  THE  DITCH 

The  ditch  resulting  from  the  explosion  will  be  rough  and  some- 
what uneven  in  depth;  occasionally,  a  few  stumps  and  other 
debris  will  roll  back  into  it.  To  open  it  up  and  even  the  grade, 
two  to  four  men,  equipped  with  phosphate  drags  and  hoes  should 
follow  the  blasters,  raking  out  the  debris  and  removing  the 
humps.  This  work  can  be  done  in  a  comparatively  short  time, 
and  greatly  improves  the  ditch. 


Fig.  75. — Blasting  ditch  in  tangled  underbrush. 


For  electrical  firing,  the  procedure  is  much  the  same.  A  few 
trial  shots  should  be  made  for  determining  the  proper  depth 
and  spacing  of  the  holes.  As  an  electric  cap  is  used  in  each  hole, 
it  is  possible  to  space  them  further  apart  in  the  row  than  in  the 
case  of  propagated  firing.  The  usual  distances  are  24  to  32 
inches  for  small  ditches  and  up  to  48  and  52  inches  for  large 
ditches  and  heavier  loadings.  After  the  charges  are  planted, 
the  blasting  cap  wire  from  each  is  connected  with  the  loading 


11G 


MOSQUITO  ERADICATION 


wire  from  the  blasting  machine.     The  charges  are  then  exploded 
simultaneously  by  operating  the  machine. 

For  larger  ditches,  the  loading  may  be  in  deeper  holes  and  with 
an  explosive  of  greater  strength,  or  parallel  rows  of  charges  may 
be  employed  as  already  described  in  the  case  of  propagated  blast- 


f 


Duplet,  leadinq  ir/re  h  b/ashng  machine 
,s^  (Zonnecf/nq  wipe,  fo  fead/hg  tvtnz 
fi/asf/bg  cap  iv/ms  connecfed\^ 


i  ^-'  uiasnng  cap  nrrcs  connt 


-Grac/e     qf  proposed  f//'/ch- 


Primed  dynamife. 
cartridges 


Fig.  76. — Loading  for   blasting   ditch,    having   only   a   single   row   of   holes,    by 

electrical  firing. 

ing.  Where  very  deep  ditches  are  needed,  a  wide  shallow  ditch 
should  be  blasted  first  and  then  a  row  or  two  of  holes  should  be 
blasted  in  the  bottom  of  this  ditch. 


75  (>/asHng  machine. 


Fig.   77. — Flan  of  loading  for  blasting  a  ditch,  having  2  rows  of  holes,  by  elec- 
trical firing. 

ADVANTAGES  OF  BLASTING  DITCHES 

The  personnel  required  for  blasting  ditches  is  small.  One 
laborer  should  make  the  holes,  another  distribute  the  dynamite 
in  them  under  the  direction  of  the  foreman,  a  third  and  fourth 
transport  the  dynamite  to  the  scene  of  the  blasting  and  a  fifth 
and  sixth  clean  out  the  ditch  after  the  blasting.  An  experienced 
blaster  should  be  in  charge  of  the  work. 

Under  favorable  conditions,  the  work  may  be  carried  on  at  the 
rate  of  100  to  200  feet  per  hour  by  the  propagation  method  with 
the  crew  indicated  above,  omitting  from  consideration,  of  course, 
any  preliminary  clearing  that  may  be  required. 

Costs  of  ditching  by  dynamite  vary,  of  course,  with  the 
character  of  the  soil,  size  of  the  ditch  and  number  of  roots  and 
stumps.  At  six  different  extra-cantonment  jobs  in  1918,  costs 
per  lineal  foot  were:  13,  14,  28,  18,  12  and  33  cents.  Wherever 
comparisons  with  hand  ditching  in  swamps  were  made,  it  was  the 
consensus  of  opinion  that  blasting  was  cheaper.1 

1  Transactions  of  The  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


INLAND  DRAIXAGE  117 

MACHINE  DITCHING 

The  various  types  of  ditching  and  trenching  machines  may  be 
divided  into  four  general  classes,  as  follows:  (1)  plows  and  scoops; 
(2)  wheel  excavators;  (3)  endless-chain  excavators;  and  (4) 
scraper  excavators. 

For  construction  of  open,  V-shaped  ditches — the  usual  type  of 
anti-mosquito  ditch — only  the  first  two  classes  are  generally 
used.  The  endless-chain  excavators,  designed  chiefly  for 
digging  trenches  for  installation  of  pipe,  which  are  filled  up  after 
the  pipe  is  laid,  usually  cut  a  narrow  and,  where  necessary,  a 
deep  ditch,  with  vertical  banks.  Owing  to  the  possibility  of 
frequent  cavings,  a  trench  of  such  a  shape  does  not,  as  a  rule, 
make  a  satisfactory  open  ditch. 

The  scraper  excavator  is  designed  chiefly  for  digging  very  large 
ditches  or  channels  and  does  not  appear  to  be  suited  for  the  type 
of  ditching  usually  required  in  anti-mosquito  work. 

The  last  two  types  of  trenching  machines,  therefore,  are, 
generally  speaking,  of  value  in  anti-mosquito  work  only  when  the 
use  of  tile  drains  on  a  large  scale  is  contemplated  or  when  a 
very  large  excavation,  as  a  new  channel  for  a  stream,  is 
required. 

Plows  and  scoops  are  usually  drawn  by  horses  or  mules  or 
tractors.  Almost  all  of  them  are  lacking  in  any  device  for  cutting 
accurately  to  grade,  thus  requiring  some  hand-work  to  make  the 
bottom  smooth.  There  are  many  types  of  these  implements, 
ranging  from  devices  designed  primarily  to  loosen  up  the  earth 
to  quite  elaborate  machines  that  dig  a  V-shaped  ditch  up  to  3  or 
4  feet  in  depth.  Two  types  of  this  class  of  machine  are  described 
below. 

Wheel  excavators  supply  their  own  power  for  digging  and 
traveling;  this  may  be  generated  either  by  internal  combustion 
engines  or  steam  engines  and  boilers.  Many  of  the  heavier 
machines  are  equipped  with  apron  tractors.  The  digging  is  done 
by  buckets  upon  the  rim  of  a  wheel  that  is  revolved  in  the 
trench,  and,  as  each  bucket  reaches  the  top  of  the  circle,  the  dirt 
falls  upon  a  conveyor  belt,  which  deposits  it  on  the  spoil  bank. 
A  shoe  often  follows  the  wheel,  removing  the  crumbs  and  smooth- 
ing and  grooving  the  bottom.  One  machine  of  this  type  is 
described  below. 


118 


MOSQUITO  ERADICATION 
SOME  TYPICAL  DITCHING  MACHINES 


Implement  A. — This  device1  consists  of  a  cutting  knife,  which 
loosens  the  earth,  and  a  bucket,  which  removes  it.  Two  men 
and  a  team  are  required  to  operate  this  machine.  The  cutting 
knife  is  mounted  on  a  steel  frame;  trimmers  for  widening  the 
ditch  are  bolted  to  the  end  of  it.  The  bucket,  which  holds 
about  5  cubic  feet  of  earth,  is  hinged  to  the  cutter  frame  by  steel 


Fig.  78. — Implement  A.     (After  U.  S.  Bureau  of  Public  Roads.) 


straps.  The  lower  end  of  a  wooden  handle  is  attached  to  a  loop 
near  the  bottom  of  the  bucket;  a  hook  on  it  engages  the  top  of  the 
bucket  between  guides  that  keep  the  bucket  from  tipping  while 
the  handle  is  straight.  The  depth  of  each  cutting  is  controlled 
by  an  adjustable  shoe  in  front  of  the  cutting  knife.  The  bucket, 
when  full,  slides  out  of  the  ditch,  the  handle  is  lifted  to  disengage 
the  hook  and  the  bucket  falls  on  its  side. 

Implement  B. — This  implement  consists  essentially  of  a  rever- 
sible cutting  blade  attached  to  a  steel  landside  at  an  acute  angle. 
The  cutting  blade  not  only  loosens  the  earth,  but  also  throws  it  up 
on  the  side  of  the  ditch.     The  device  may  be  reversed  to  cut  on 

1  Based  largely  on  Farmer's  Bulletin  No.  698,  U.  S.  Department  of  Agri- 
culture, 1915,  by  D.  L.  Yarnell,.' 


INLAND  DRAINAGE 


119 


either  side  and  may  also  be  adjusted  as  to  width  of  ditch.  It 
comes  in  various  sizes  and  weighs  290  to  425  pounds.  Four  to 
six  horses  or  a  tractor  are  required  to  operate  the  largest  model, 
while  the  smallest  may  be  operated  with  2  or  3  horses.  It  does 
not,  of  course,  cut  accurately  to  grade. 


Fig.   79. — Implement  B.      {Courtesy  of  Owensboro  Ditcher  and  Grader  Company.) 


Implement  C. — This  machine  is  one  of  the  various  types  of 
wheel  excavators  and,  of  course,  is  considerably  more  expensive 
than  the  two  machines  described  heretofore.  However,  it 
follows  grade  very  closely  and  usually  makes  a  perfect  ditch  at 
one  cut.  Only  two  men  as  a  rule  are  required  to  operate  it,  the 
average  daily  operating  cost,  according  to  the  manufacturers, 
running  from  $16.75  for  the  smallest  model  to  $43  for  the  largest 
model.  This  machine  will  average  half  a  mile  of  completed 
ditch  of  the  usual  anti-mosquito  type  and  ordinary  size  every 
day  according  to  the  manufacturers. 


120  MOSQUITO  ERADICATION 

There  seems  to  be  no  doubt  that,  in  localities  to  which  it  is 
suited,  machine  ditching  is  considerably  cheaper  than  ditching  by 
hand. 


FlG.  80.— Implement    C.     (Courtesy    of   Buckeye    Traction    Ditcher    Company.) 

MAINTENANCE  OF  OPEN  DITCHES 

One  of  the  most  objectionable  features  of  the  open  ditch,  from 
an  anti-mosquito  viewpoint,  is  the  necessity  of  maintaining  it  in 


INLAND  DRAINAGE 


121 


proper  condition — that  is,  keeping  it  in  such  shape  that  it  will 
properly  drain  the  area  it  is  supposed  to  drain  and  also  keeping 
it  in  such  shape  that  it  itself  will  not  become  a  breeding  place. 
Due  to  local  topography,  character  of  soil  and  other  conditions, 
some  open  ditches  or  parts  thereof  may  be  relatively  expensive  to 
keep  in  shape. 


Fig.  81. — Cleaning  out  road-side  ditches  with  a  ditching  machine. 

In  order  to  preserve  their  ability  to  drain  the  areas  they  are 
intended  to  drain,  ditches  should  be  kept  to  the  established 
grade  and  proper  cross-section;  in  order  to  prevent  ditches  from 
themselves  becoming  breeding-places,  obstructions,  such  as 
sticks,  leaves  and  other  floatage,  deposits  of  silt  and  sand  and  all 
vegetable  growth,  including  algae,  should  be  removed  from  the 
ditch  periodically.  Shovels  and  hoes  are  the  tools  best  suited 
to  this  work.  Where  the  ditch  is  in  soft  ground,  great  care  is 
required  not  to  spoil  the  grade. 

For  the  removal  of  rank  grass  and  weeds  from  ditches,  a  weed- 


122 


MOSQUITO  ERADICATION 


INLAND  DRAINAGE  123 

burner  may  sometimes  be  used  to  advantage,   although    this 
method  is  some  more  costly  than  doing  it  by  hand. 

THE  WEED -BURNER 

The  weed-burner  consists  of  a  steel  tank  (large  enough  to  hold 
15  gallons  of  kerosene  and  to  leave  a  good-sized  air-space  above 
it)  equipped  with  a  double-acting,  long-stroke  pump,  which  has 
automatic  valves  and  a  pressure  gage,  and  two  burners,  each 
connected  by  a  long  rubber  hose  to  metal  pipes  reaching  to  the 
bottom  of  the  tank.  The  burner  is  a  short  length  of  straight 
pipe  with  a  coil  at  the  end.  The  oil  passes  down  the  straight 
pipe,  through  the  coil  and  back  to  the  base  of  the  coil,  where  it  is 
atomized  through  a  nozzle.  To  begin  operations,  the  supply 
valves  are  closed,  the  burner  coils  heated  until  red  and  the  air 
pressure  brought  to  40  pounds.  Upon  opening  the  supply 
valves,  the  oil  is  forced  through  the  hot  coils  and  readily  ignites, 
producing  a  bluish  flame  about  30  inches  long  and  4  inches  in 
diameter.  If  the  coil  is  not  heated  sufficiently,  the  flame  will  be 
of  a  reddish  color  and  of  low  heat  value. 

Three  men  are  considered  necessary  for  the  operation  of  this 
device — one  at  each  burner  and  a  third  pumping  to  keep  the 
pressure  up  to  40  pounds. 

Shaw1  reports  that  the  cost  of  burning  out  with  this  device  a 
ditch  overgrown  with  weeds  and  grass  amounted  to  1.4  cents  a 
lineal  foot  as  against  a  cost  of  0.35  cent  by  hand.  Lenert1 
reports  that  a  similar  burning  cost  1.5  cents  a  lineal  foot. 

Several  commercial  arsenical  preparations  designed  to  kill 
weeds  are  also  on  the  market  and  may  be  used  in  anti-mosquito 
work,  where  they  will  not  endanger  stock. 

In  periods  of  drought,  a  ditch  may  become  a  series  of  stagnant 
pools.  A  small  temporary  channel  may  then  be  made  to  concen- 
trate and  drain  off  this  water,  or,  if  the  holes  are  not  too  numer- 
ous, they  may  be  filled  with  stone  or  earth.  Otherwise,  they 
may  be  oiled  or  stocked  with  fish. 

In  cases  where  the  banks  of  ditches  in  pasture  lands  are  flat 
and  soft,  both  above  and  below  the  flow-line,  deep  impressions, 
which  hold  water,  are  sometimes  made  by  the  hoofs  of  cattle  and 
horses.  Where  practicable,  such  soft  areas  should  be  protected 
by  fences,  and  a  barrel  without  a  bottom  should  be  installed  at  a 

1  Transactions  of  Second  Annual  Anti-Malaria  Conference  of  Sanitary- 
Engineers,  U.  S.  Public  Health  Service,  1921. 


121 


MOSQUITO  ERA DIC A TION 


suitable  place  where  it  will  remain  filled  with  water  for  the  stock 
to  drink. 

While  recleaning  of  open  ditches  along  the  lines  described  will 
be  required  from  time  to  time  during  the  mosquito  season,  it  is  a 
good  plan  to  get  all  such  ditches  in  shape  early  in  the  season 
before  the  first  new  broods  of  mosquitoes  appear. 

MAINTENANCE  COSTS 

Maintenance  costs  vary  considerably  with  local  conditions.  In 
areas  where  weeds  grow  rapidly,  they  probably  will  prove  the 


%4**&H 


%■ 


Fig.  83. — Cleaning  out  an  old,  clogged  up  ditch  by  hand. 


most  troublesome  factor.  In  some  places,  the  writer  has  found 
it  necessary  to  remove  these  growths  every  month  or  so;  this 
runs  into  a  large  amount  of  money  in  a  season  on  a  large  project. 
Again,  heavy  rains,  resulting  in  rapid  run-offs,  sometimes  ruin  the 
grade  of  miles  of  ditches;  sand  and  mud  will  be  deposited  at  many 
places,  while  deep  holes  will  be  cut  into  the  banks  and  bottom  at 
others. 

During  1918,  on  a  job  with  which  the  writer  was  connected, 


INLAND  DRAINAGE 


125 


approximately  29  miles  of  ditches  were  maintained  at  a  cost  of 
$0,045  a  foot  or  $241.52  a  mile  for  the  season;  estimating  the 
season  as  lasting  6  months,  the  cost  was  less  than  $0,008  a  foot  or 
$40.25  a  mile  a  month.  These  ditches  were  kept  in  almost  per- 
fect condition  at  all  times — free  from  grass  and  weeds  and 
obstructions  of  all  kinds. 

PERMANENT  LINING  OF  ANTI-MOSQUITO  DITCHES 

Anti-mosquito  drainage  ditches  may  be  lined  to  advantage, 
where  excessive  erosion  takes  place  or  where  maintenance  costs 
otherwise  become  excessive. 


Fig.  84. — Section  of  ditch  lined  with  redwood  boards. 

Materials  usually  employed  for  lining  ditches  are  concrete, 
stone  set  in  mortar  and  planks.  While  the  former  are  more 
expensive,  they  are  more  permanent  and  generally  give  more 
satisfaction  in  the  long  run. 

LePrince1  says:  "Lined  ditches  are  more  permanent,  easily  cleaned, 
require  less  inspection  and  are  ultimately  less  costly.  At  some  of  the 
settlements  in  the  Panama  Canal  Zone,  it  was  found  that  a  large  saving 
was  made  by  lining  certain  ditches  and  parts  of  ditches  with  concrete 
as  against  repeated  regrading,  cleaning  and  oiling  of  open  earth  ditches." 

As  a  rule,  the  lining  should  be  U-shaped  with  sloping  sides;  it  is 
not  always  necessary,  however,  to  line  the  whole  depth  of  the 

1  "Malaria  Control;  Drainage  As  An  Anti-mosquito  Measure,"  U.  S. 
Public  Health  Service,    1915. 


126 


MOSQUITO  ERADICATION 


ditch.  The  lining  of  the  bottom  and  sides  up  to  3  or  4  inches 
above  the  normal  water  line  generally  will  answer  for  small 
ditches.  In  wide  ditches,  the  bottom  should  slope  toward  the 
center  and  the  side  walls  may  often  be  nearly  vertical. 


Fig.  85. — Openjiitch  lined  with  concrete. 

A  smooth  or  fancy  finish,  which  adds  to  the  cost,  is  not  essen- 
tial. The  ditch  may  be  lined  roughly  with  flat  stones,  the  holes 
being  chinked  up  and  mortar  plastered  "about  ]them.     Where 


Hzm" 


( Ho  jtfied  offer  iefripce) 

Fig.   86. — Cross-section  of  lined  main  ditch  and  unlined  lateral. 


flat  stones  are  not  available,  a  2-inch  layer  of  concrete,  reinforced 
with  chicken  wire  of  about  2-inch  mesh  may  be  used. 
LePrince  continues: 


INLAND  DRAINAGE 


127 


<^53S^ 


"In  order  to  avoid  scouring  out  of  banks  above  the  lining  by  storm 
water,  particularly  at  sharp  curves  or  bends  of  ditches,  the  outer 
wall  lining  should  be  raised  to  meet  the  condition,  or  the  ditch  may  be 
widened  or  key-walls  installed.  Key-walls  .  .  .  will  prevent  the 
side-scour  and  under-scour  of  linings  of  straight  ditches  of  heavy  grades. 
The  key-wall  should  extend  6  inches  to  a  foot  or  more  into  the  ground 
below  the  bottom  ditch  lining.  Branch  ditches  should  enter  lined 
ditches  at  an  acute  angle  or  on 
a  curve,  with  a  sharp  grade  near 
the  junction. 

"In  all  cases,  weep-holes  or 
seepage-holes,  sloping  toward  the 
center  or  bottom  of  the  ditch 
and  located  just  above  the  key- 
wall,  should  be  provided.  This 
is  required  to  prevent  the  effect 
of  currents  which  may  be  under 
or  behind  the  concrete  ditch  lining.  Weep-holes  should  be  made  in 
side  walls  before  the  concrete  has  set.  They  should  be  used  wherever 
water  might  be  behind  the  lining." 


Fig.  87.- 


(MoJifieJ  after  U Prince) 

-Cross-section  of  key-wall. 


,  S/one  and  qmve/ 


SUB-SURFACE  TILE  DRAINS 

Tile  drainage  within  the  last  25  years  has  become  of  great 
importance  as  an  agricultural  measure  to  improve  crops  by 
reducing  excessive  moisture  in  the  soil.  Such  drainage  is  of  great 
value  in  anti-mosquito  work,  inasmuch  as  it 
lowers  the  water-table,  thus  allowing  pools  of 
surface  water  to  be  absorbed  more  rapidly. 
Tile  drains  also  may  be  used  to  intercept  seepage 
water  and  for  other  purposes  in  connection  with 
anti-mosquito  drainage. 

Sometimes  in  an  anti-mosquito  campaign 
it  is  possible  to  persuade  owners  of  low-lying, 
swampy  lands  about  a  town  to  tile  drain  them 
for  agricultural  purposes.  Where  this  can  be  done,  a  double 
benefit  is  derived — the  lands  are  made  more  productive  and 
the  mosquito  breeding-places  thereon  permanently  eliminated. 

Again,  in  purely  anti-mosquito  work,  it  has  been  found  that  in 
the  long  run  it  frequently  pays  to  substitute  tile  drains  for  open 
ditches.  According  to  the  report  of  the  Panama  Canal  Zone 
Health  Department  for  1919,  substitution  of  tile  drains  for  open 
ditches  in  pasture  lands  resulted  in  a  considerable  saving  by 


Fig.  88. — Cross- 
section  of  fill  over 
intercepting  tile 
drain. 


128  MOSQUITO  ERADICATION 

rendering  unnecessary  previous  oiling  of  hoof-prints,  etc.,  along 
their  margins  in  the  wet  season.  Another  considerable  economy 
resulted  from  elimination  of  the  necessity  for  periodical  cleaning 
of  grass  and  weeds  from  open  ditches. 

TILE  DRAINS  VERSUS  OPEN  DITCHES 

Ditches  in  which  drainage  tiles  are  to  be  installed  must  follow 
grade  exactly;  hence,  they  should  be  laid  out  by  instrument  or 
other  accurate  method  and  the  bottom  finishing  checked  from 
time  to  time.  Where  the  fall  is  less  than  2  inches  to  100  feet,  very 
careful  work  is  required. 

Tile  drains  generally  should  be  laid  from  2  to  4  feet  deep, 
depending  upon  character  of  soil  and  other  local  conditions.     As 

the  ditches  in  which  they  are  laid 
are  filled  up  as  soon  as  the  laying 
is  completed,  they  need  be  of  no 
particular  shape,  such  as  is  re- 
quired in  the  case  of  open  ditches; 
they  may  be  dug  with  vertical  sides, 
if  the  nature  of  the  soil  will  permit. 
In  digging  ditches  for  tile  clrain- 
Fig.   89. — Cross-section  of  outlet  age  by  hand,  special  tile  spades  are 

for  a  tile  drain.  i,  ■,         A        , ,  £    i 

generally  used.  Another  useful 
instrument  is  the  drain  scoop,  which  comes  in  various  sizes  to  suit 
the  size  of  tile.  However,  a  very  large  proportion  of  the  ditches 
for  agricultural  tile  drainage  are  dug  by  machinery  today. 

A  system  of  tile  drainage  may  consist  of  a  main,  sub-mains, 
laterals  and  sub-laterals,  or  only  a  main  and  a  lateral.  The  main 
is  the  drain  through  which  all  the  water  eventually  flows.  Some- 
times, only  a  single  line  may  be  needed. 

A  proper  outlet  for  the  main  should  be  provided  in  all  cases  in 
order  to  prevent  caving  and  possible  closing  of  the  pipe.  Prob- 
ably the  best  protection  is  a  concrete  wall,  into  which  the  end  of 
the  pipe  is  set.  Where  the  outlet  is  low  and  liable  to  be  sub- 
merged in  time  of  flood,  a  valve  should  be  installed  to  keep  the 
water  from  backing  into  the  drain. 

LAYING   OUT  A  TILE   DRAINAGE   SYSTEM 

In  laying  out  a  tile  drainage  system,  as  few  mains  and  as  many 
long  laterals  should  be  used  as  possible,  as  a  rule,  since,  near  the 
mains,  both  the  laterals  and  the  mains  drain  the  land.     For  this 


INLAND  DRAINAGE 


129 


reason,  the  system  shown  in  Fig.  91  is  preferable  to  that  shown  in 
Fig.  90,  since  the  cost  is  less  and  the  drainage  more  uniform. 
In  the  East,  for  general  farming  purposes,  the  laterals  are 
placed  from  32  to  70  feet  apart.  In  the  Middle  West,  on  the 
higher  lands  and  closer  soils,  132  feet  frequently  has  proved 
satisfactory.  On  level  lands  with  porous  subsoils,  drains  from, 
160  to  192  feet  apart  have  given  good  service.     For  truck  land 


Do  u 


/e 


d  r^/incd / 


!Z 


U.5.   Dcpar/wcnf-  of  Acjncu/fvre  (Afcr5mith) 


Fig.  90. — Too  much  double-drain- 
ing— a  waste  of  money. 


Fig.  91. — Double-draining  re- 
duced to  a  minimum  by  proper 
design. 


the  laterals   should   be  closer  together  than  for  land  on  which 
general  farming  is  carried  on. 

No  tile  less  than  3  inches  in  diameter  should  be  used,  and  best 
practice  today  in  the  Middle  West  seems  to  be  to  make  5  inches  the 
minimum  size.  However,  no  hard  and  fast  rule  can  be  given. 
According  to  Smith,1  in  the  dark  silt-loam  soils  of  Illinois  and 
Iowa,\where  the  rain-fall  approximates  36  inches  a  year,  an  8- 
inch  tile  with  a  fall  of  2  inches  to  100  feet  will  furnish  an  outlet  for 

l"  Tile  Drainage  on  the  Farm,"  Farmer's  Bulletin  No.  524,  U.  S.  Department 
of  Agriculture,  1917. 
9 


130  MOSQUITO  ERADICATION 

the  complete  drainage  of  40  acres,  while  a  4-inch  tile  will  drain 
only  6  acres.  On  the  level  soils  of  the  South  Atlantic  and  Gulf 
States,  where  the  rain-fall  is  heavier,  only  about  three-fourths  of 
these  areas  can  be  drained  with  the  same  size  of  tile,  according  to 
the  same  writer. 

PLACING  THE  TILE 

"Laying  the  tile,  like  digging  the  ditch,  should  begin  at  the  outlet," 
says  Smith.1  "  Under  ordinary  conditions,  tile  should  be  laid  every  day 
as  far  as  the  ditch  is  made.  Any  delay  in  laying  may  cause  injury  to  the 
ditch  by  rain  or  by  particles  falling  into  it.  If  the  banks  are  likely  to 
cave,  the  tile  should  be  laid  as  fast  as  the  ditch  is  completed. 

"The  smaller  sizes  are  laid  from  the  bank  with  a  hook.  Large  sizes 
must  be  laid  by  hand  from  the  bottom  of  the  ditch.  All  mis-shaped  and 
cracked  tile  should  be  discarded.  If  a  tile  does  not  join  closely  with  a 
preceding  one,  it  should  be  turned  over  until  it  fits  at  the  top.  Any 
large  cracks  are  covered  with  pieces  of  tile.  Where  a  lateral  joins  to  a 
main  or  sub-main,  the  connection  should  be  made  with  a  Y.  Neither 
a  T  nor  an  elbow  is  desirable,  as  these  check  the  flow  of  the  water. 

"When  the  tile  are  laid  and  inspected,  they  are  ready  for  priming. 
This  is  done  by  caving  a  little  earth  from  the  sides  of  the  ditch  and  letting 
it  settle  gently,  so  as  to  keep  from  knocking  the  tile  out  of  line.  In 
sandy  soils,  there  may  be  danger  of  sand  entering  the  tiles  and  clogging 
the  drain.  This  can  be  prevented  by  covering  the  joints  with  pieces  of 
old  sacks  or  straw. 

"After  the  tile  are  primed,  they  may  remain  without  injury  for  several 
days  until  all  the  ditches  are  ready  for  filling.  If  the  soil  is  close  and  it  is 
desirable  to  aid  the  water  in  reaching  the  tile  quickly,  the  ditch  can  be 
partially  filled  with  straw  or  brush,  or,  better  still,  with  stones  and 
pieces  of  brick.  Under  ordinary  conditions,  the  ditch  is  most  easily 
filled  with  a  turn-plow  and  an  evener,  which  is  12  or  14  feet  long.  Two 
horses  are  hitched  to  this  plow,  one  on  each  side  of  the  ditch  and,  with 
one  man  to  lead  or  drive  and  another  to  hold  the  plow,  the  earth  is 
turned  in.  There  may  be  extraordinary  conditions,  however,  when  a 
plow  cannot  be  used.  By  placing  the  team  on  one  side  of  the  ditch  and  a 
wooden  scraper  on  the  other  side  in  such  cases,  the  dirt  can  be  pulled  in 
rapidly.  Filling  by  hand  is  usually  the  most  difficult  and  most  expen- 
sive method." 

In  laying  tile  for  the  purpose  of  intercepting  seepage  water, 
best  practice  seems  to  call  for  a  stone  or  gravel  fill  over  the  tile, 
instead  of  the  usual  earth  fill. 

i"Tile'Drainage  on  the  Farm,"  Farmer's  Bulletin  No.  524,  U.  S.  Department 
of  Agriculture,  1917. 


INLAND  DRAINAGE  131 

TILE  DRAINAGE  COSTS 

Tile  drainage  costs  may  be  divided  into  two  phases — that  of 
the  tile  delivered  at  the  trench  and  that  of  the  digging,  laying 
and  filling. 

Prices  of  tile  vary  in  the  different  sections  of  the  United  States, 
being  cheapest  in  the  Middle  West.  In  the  East  and  South, 
tile  is  about  50  per  cent  higher  than  in  the  Middle  West,  and  in 
the  Far  West  about  70  per  cent  higher,  according  to  Smith.1 
Haulage  costs  depend,  of  course,  upon  the  distance. 

"Digging  the  ditch  and  laying  and  priming  the  tile  are  usually  figured 
as  one  operation,"  says  Smith.1  "This  is  done  either  at  so  much  per  rod 
or  by  the  day,  the  former  being  the  more  common  practice  ...  On 
ordinary  soils  in  the  Middle  West,  the  average  capacity  of  a  good 
workman  with  a  3-foot  ditch  and  not  over  5-inch  tile  is  10  rods  a  day. 
In  the  East  and  South  sometimes,  on  account  of  the  character  of  the 
soil,  the  capacity  of  a  man  is  from  4  to  8  rods,  with  the  same  depth  and 
size  of  tile." 

"For  tile  trenching  and  laying  by  hand,"  says  Yarnell,2  "where 
experienced  men  are  employed,  the  rate  of  progress  for  one  bottom  man 
and  one  top  man,  for  the  smaller  sizes  of  tile  not  more  than  3  feet  deep, 
is  ordinarily  15  to  30  rods  per  day,  depending  largely  upon  soil  condi- 
tions. In  some  sections  of  the  country  where  the  use  of  unskilled  colored 
labor  is  necessary,  the  same  number  of  men  will  put  in,  even  with  good 
supervision,  only  5  to  8  rods  per  day  per  man." 

VERTICAL  DRAINAGE 

That  vertical  drainage  is  an  economical  and  effective  method 
of  eliminating  pools  of  standing  water  in  districts  where  the  water 
is  held  by  an  impervious  stratum  overlaying  a  pervious  one  has 
been  repeatedly  demonstrated.  The  principle  of  course,  is  to 
sink  a  hole  through  the  impervious  layer  so  that  the  water  may 
escape  through  the  porous  material.  This  may  be  sand  or  gravel 
or  limestone  and  other  formations  that  contain  seams  and 
fissures. 

While  there  is  a  degree  of  uncertainty  about  vertical  drainage, 
the  costs  are  so  low,  where  the  pervious  material  lies  close  to  the 

1  "Tile  Drainage  on  the  Farm,"  Farmer's  Bulletin  524,  U.  S.  Department  of 
Agriculture,  1917. 

?"  Trenching  Machinery  L'sed  for  the  Construction  of  Trenches  for  Tile 
Drains,"  Farmer's  Bulletin  698,  U.  S.  Department  of  Agriculture,  1915. 


132 


MOSQUITO  ERADICATION 


surface,  as  compared  with  an  expensive  ditching  project,  that  it  is 
often  well  worth  while  to  try  it  out  in  favorable  areas. 

As  a  rule,  the  holes  should  be  lined  to  prevent  clogging  up  the 
avenue  of  escape  for  the  water  by  erosion.     For  the  same  reason, 

it  is  often  desirable  to  install  a  drain-head 
or  other  device  to  keep  out  the  coarser 
material  carried  along  by  the  water. 

Gorman1  describes  a  typical  operation, 
which  resulted  in  the  complete  drying 
up  of  a  pond  covering  nearly  an  acre,  as 
follows : 

TYPICAL  VERTICAL  DRAINAGE 
OPERATION 

"Beginning  at  a  few  feet  from  the  water's 
edge,  on  shore,  at  a  shallow  part  of  the  pond, 
a  hole  was  dug  to  the  limestone  stratum  with 
a  post-hole  digger.  Then,  with  a  long  drill,  a 
hole  12  inches  deep  was  made  in  the  lime- 
stone and  a  stick  of  dynamite  inserted,  well- 
packed  and  exploded.  The  hole  was  then 
cleared  out,  the  drill  again  used  and  another 
stick  of  dynamite  exploded.  This  was  con- 
tinued for  three  or  four  times,  until  drilling 
had  been  carried  to  a  depth  of  4  feet  or  more 
in  the  limestone.  Water  from  the  pond  was 
then  directed  into  the  hole.  This  same 
thing  was  done  at  two  or  three  other  places 
around  the  pond  ...  As  the  water  drain- 
ed and  the  pond  became  smaller,  other  holes 
Fig.  92.— Sketch  of  a  verti-  were  dynamited  as   described   above,   and, 

after  eight  holes  had  been  made,  the  pond 
was  dry.  By  observing  the  rapidity  with  which  the  different  holes 
drained,  it  was  noticed  that  four  of  them  were  especially  effective  .  .  . 
showing  that,  in  the  case  of  these  four,  seams  in  the  limestone  had  been 
reached. 

"These  four  effective  drains  were  dynamited  several  more  times  and 
then,  at  each  of  them,  holes  2  feet  in  diameter  were  dug  through  the 
clay  to  the  limestone.  In  these  holes,  resting  on  the  limestone  stratum, 
12-inch  vitrified  clay  sewer  pipes  were  placed  vertically,  being  built  up 
to  a  few  inches  above  the  ground.     The  rest  of  the  hole  around  the  pipe 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers,  U.  S. 
Public  Health  Service,  1919. 


/.imeshne. ' 


INLAND  DRAINAGE 


133 


was  then  filled  with  coarse  stone  and  cinders.  A  main  ditch  was  then 
dug  in  the  center  of  the  pond  its  entire  length,  with  occasional  laterals. 
This  main  ditch  and  the  lateral  led  to  the  four  effective  drains  described 
above. 

"The  cost  of  this  work,  labor  at  30  cents  per  hour,  was  S173.42.  This 
included  1,500  feet  of  ditching  and  the  work  on  the  four  rejected  drains, 
which  were  filled  in." 

Bishop1  describes  a  vertical  drainage  project,  in  which  it  was 
necessary  to  pierce  40  to  50  feet  of  clay  before  the  limestone  was 
reached.  The  holes  were  dug  with  an  ordinary  post-hole  auger 
with  sectional  pipe  extensions  at  a  cost  of  2  cents  per  foot.  It 
has  been  found,  however,  that  the  post-hole  auger  will  not  work 
in  certain  soils. 

VERTICAL  DRAINAGE  FOR  LARGE  AREAS 

Sometimes,  when  the  area  to  be  drained  is  extensive,  it  is 
necessary  to  make  the  hole  of  considerable  size.     This,  of  course, 


^  Drain-  head 


m>>>>;wvv>>»w»»>>)>>,MMWW>M»mww*^^ 


/ 


^Popt 


Shaft 


Fig.  93. — Profile  of  pool,  drain-head  and  shaft. 

greatly  increases  the  cost  of  the  operation.  Stromquist2  describes 
such  a  hole,  which  drained  a  pond  covering  more  than  40  acres 
in  extent. 

A  shaft,  7  feet  square,  was  sunk  to  a  depth  of  about  41  feet, 
at  which  point  a  fissure,  about  4K  feet  high  by  \lA  feet  wide 
was  found  in  a  vertical  wall  of  limestone.  The  shaft  was  curbed 
with  2  by  6  material,  double  braced,  at  intervals  of  3  feet,  and 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
IT.  S.  Public  Health  Service,  1919. 

2  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers,  U.  S. 
Public  Health  Sendee,  1919. 


134  MOSQUITO  ERADICATION 

2  by  12-inch  sheathing.  A  flume  was  built  from  one  side  of  the 
shaft  to  the  end  of  the  ditch  connecting  with  the  lake.  The  out- 
let thus  formed  proved  sufficient  to  drain  the  entire  lake  and 
keep  it  dry. 

Sometimes,  if  the  fissure  be  small,  there  is  a  tendency  for  the 
hole  to  silt  up,  especially  when  the  water  enters  the  hole  directly. 
This  may  be  avoided  by  the  use  of  a  drain-head,  designed  to 
keep  out  floating  matter  and  the  coarser  sediment.  Such  a 
drain-head  may  be  an  elongated,  narrow  box,  laid  as  a  pipe 


cover  or e/oc"  M  ,ovfs/d(. 


ovrs/ae  screen 


inside,  screen 


Shaft- 
Fig.  94. — Sketch  of  a  drain-head  for  vertical  drainage. 

from  the  ditch  to  the  hole;  the  end  toward  the  ditch  should  be 
heavily  screened  and  the  other  tightly  closed;  a  hole  in  the 
bottom  near  the  closed  end,  through  which  the  water  is  to  enter 
the  shaft,  also  should  be  well  screened;  a  door  on  the  top  of  the 
box  will  allow  this  latter  screen  to  be  cleaned  from  time  to 
time;  the  entrance  screen  of  course  may  be  kept  clean  from  the 
outside. 

STREAM  RE-CHANNELING 

Contrary  to  the  popular  belief  that  mosquitoes  breed  only  in 
stagnant  water,  they  may  often  be  found  breeding  in  abundance 
in  numerous  flowing  streams,  since  in  most  streams  there  are 
many  places  where  the  current  is  almost  imperceptible. 

Thus,  in  a  stream  in  flat  country,  where  the  fall  is  slight,  there 
are  apt  to  be  many  quiet  pools,  suitable  for  breeding.  Even  in 
a  stream  with  a  considerable  fall,  obstructions  may  stop  the 
current  or  a  soft  bottom  may  wash  out,  resulting  in  a  large,  deep 
hole.  Furthermore,  the  numerous  bends  in  most  streams  cause 
a  considerable  loss  of  fall  and  hence  of  velocity. 

LePrince1  says: 

"A  stream  should  be  made  to  have  steep  banks  directly  above 
and  below  the  flow  line,  uniform  grade  and  width  and  a  straight  course, 

1  "Malaria  Control:  Drainage  as  an  Anti-malaria  Measure,"  U.  S. 
Public  Health  Service,  1915. 


INLAND  DRAINAGE 


135 


and  be  free  from  grass,  sticks,  stones  or  other  obstructions  that  would 
interfere  with  the  current.  These  conditions  are  seldom  found  in 
nature,  but  the  nearer  a  stream  approaches  them  the  less  will  mosquito 
breeding  be  found." 


(Photos  by  E.  H.  Magoon,  C.  E.) 
Fig.  95.  Fig.  96. 

Fig.  95. — This  pretty  pool  in  a  stream-bed  was  a  breeding-place  for  Anopheles. 
Mosquito  control  was  secured  by  connecting  it  with  a  nearby  larger  pool  that 
was  stocked  with  minnows. 

Fig.  96. — Water  in  a  ditch  confined  to  a  narrow  channel  in  order  to  facilitate 
mosquito  control.  The  ditch  is  oiled  by  means  of  a  drip-barrel  at  its 
upper  end. 

BLASTING  NEW  CHANNELS 

The  writer  has  found  that,  if  the  stream  is  very  crooked  and 
much  regrading  is  necesssary,  it  frequently  will  pay  to  disregard 
the  old  channel  completely  and  make  a  new  and  straight  one. 
If  the  soil  conditions  are  adapted  to  it — that  is,  if  the  soil  is 
wet  and  water-soaked — dynamiting  probably  will  prove  to  be 
the  cheapest  method.  The  writer  once  had  occasion  to  re- 
channel  with  dynamite  about  a  mile  of  a  large  creek  in  Georgia, 
which  averaged  20  feet  wide  and  from  1  to  6  feet  deep.  A  hard 
sand  stratum  which  underlay  the  soft  surface  ooze  at  a  depth 
of  about  6  feet  provided  an  ideal  base  for  reaction  of  the  explosion. 


130  MOSQUITO  ERADICATION 

The  cost  was  33  cents  per  lineal  foot.     The  total  cost  of  $1,516.35 
was  divided  as  follows: 

Labor  cost  of  dynamiting $     123.75 

Cost  of  dynamite 1,260.10 

Cost  of  cleaning  channel 132 .  50 

Where  the  old  channel  is  not  so  crooked,  however,  it  may  be 
cheaper  to  utilize  it,  straightening  and  regrading  it  where  most 


Fig.   97. — A  new   channel  for  a  stream.      Note   the  straight   course   and   clean 

edges. 

needed.  Places  where  the  stream  widens  out,  probably  will 
give  the  most  trouble.  The  best  way  of  dealing  with  these  is 
to  dig  out  a  channel  and  use  boards  or  a  rough  plastered  wall, 
where  necessary,  to  keep  it  open;  if  boards  are  used,  they  should 
be  well  filled  in  behind.  Sharp  bends  where  storm  water  may 
scour  out  and  erode  the  banks  may  also  be  advantageously 
treated  in  this  way. 

CLEARING  STREAMS  OF  LOGS,  ETC. 

Where  the  bottom  of  the  stream  is  soft,  so  that  large  pockets 
or  pools  have  formed  in  the  channel,  such  holes  may  be  filled 


INLAND  DRAINAGE 


137 


with  stone  in  such  manner  as  to  prevent  further  extension  of 
them. 

Sometimes  streams  will  be  found  clogged  up  with  log  jams, 
started  by  individual  logs  catching  against  stumps  and  trees  on 
the  bank.  Such  jams  will  range  in  size  from  20  to  30  logs  up  to 
more  than  a  thousand.  According  to  Williams1  the  best  way  to 
deal  with  them  is  to  explode  three  or  four  bundles  of  dynamite 
(20  pounds  each)  among  the  logs  at  the  lower  end  of  the  jam; 


PcnVS  of 

planted  dynamite^ ' 


)  j^O/d  channel 


Bewre  After 

Fig.  98. — Creek  before  and  after  straightening  by  blasting. 

the  explosion  will  loosen  the  logs  and  the  majority  of  them  will 
start  downstream;  a  sufficient  force  of  laborers  should  be  posted 
along  the  banks  to  prevent  any  new  jam  formations. 

Where  the  logs  are  not  so  numerous  but  are  scattered  out 
along  the  banks,  they  may  be  cut  loose  by  laborers  and  then 
hauled  up  out  of  the  water  by  means  of  teams. 

Any  other  obstructions,  together  with  weeds,  grass,  algae  and 
similar  growths,  should  be  removed  from  streams  periodically. 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1910. 


138 


MOSQUITO  ERADICATION 


Streams  which,  during  a  period  of  drought,  partly  dry  up, 
leaving  depressions  or  "pot-holes"  along  their  courses,  should  be 
treated  similarly  to  ditches  which  give  rise  to  similar  troubles. 

FILLING 

Collections  of  water  that  cannot  economically  be  drained 
should  be  filled  when  practicable.  Wet  areas  that  are  most 
expensive  to  control  should  be  eliminated  first.  Shallow  water 
in  places  that  are  too  low  to  be  drained  may  be  concentrated 
by  filling,  so  that  the  remaining  water  is  easier  and  cheaper  to 
control. 


{Photo  by  E.  H.  Magoon,  C.  E.) 
Fig.  99.— Making  a  fill. 

Frequently,  it  is  possible  to  procure  that  city  trash  be  dumped 
at  the  place  it  is  desired  to  fill.  This  course  may  not  be  practi- 
cable, however,  where  the  haul  is  too  far  or  where  the  place  is  in 
a  thickly-inhabited  section.  In  all  cases,  the  trash  must  be 
levelled  off  so  as  to  prevent  the  formation  of  pools,  and  should  be 
covered  with  6  inches  or  more  of  earth  in  order  to  prevent  odors, 
especially  in  summer.  Under  no  circumstance  should  potential 
water-containers,  such  as  old  cans,  bottles,  etc.,  be  left  exposed. 

Porous  materials,  such  as  cinders,  are  very  good  for  filling. 
In  the  vicinity  of  lumber-mills,  waste,  saw-dust  and  shavings 
are  available  in  quantity,  and,  when  used  for  filling,  should  extend 
several  inches  above  the  surface  of  the  ground. 

Areas  kept  wet  by  seepage  water  can  seldom  be  satisfactorily 
treated  by  making  a  shallow  fill  of  earth. 


CHAPTER  VII 

SALT  MARSH  DRAINAGE 

THE    SALT    MARSH    PROBLEM    IN    GENERAL 

The  salt  marshes  that  abound  along  the  Eastern  and  Southern 
coasts  of  the  United  States  from  New  York  to  Mexico  constitute 
probably  the  greatest  single  breeder  of  mosquitoes  in  the  country. 

These  low-lying  marshes,  swept  from  time  to  time  by  the  tides, 
which  fill  every  hole  and  depression,  make  ideal  breeding  places 
and  present  probably  the  most  difficult  problem  that  there  is 
from  an  anti-mosquito  point  of  view,  not  only  on  account  of  the 
huge  areas  they  cover,  but  also  on  account  of  the  enormous 
expense  involved. 

Fortunately,  not  all  parts  of  the  salt  marsh  breed  mosquitoes 
in  equal  abundance,  owing  to  the  activities  of  larva-destroying 
fish,  which,  when  they  are  present  in  considerable  numbers,  eat 
the  larvae  nearly  as  fast  as  they  hatch  from  the  eggs.  However, 
there  are  many  parts  of  the  marsh  that  the  fish  cannot  reach,  such 
as  high-lying  and  shut-in  meadows  over  which  the  tides  rise  only 
occasionally.  Even  where  an  extra  high  tide  has  stocked  the 
holes  with  fish,  the  water  soon  dries  up  and  the  fish  die;  then,  rain 
water  fills  the  holes,  larva  appear  and  a  brood  of  mosquitoes 
gets  on  the  wing. 

The  problem  of  preventing  mosquito  breeding  in  salt  marshes 
is  thus  seen  to  be  one  of  determining  just  what  parts  of  the  marsh 
constitute  mosquito  production  areas  and  then  so  treating  them 
that  the  tide-water  will  run  off  at  frequent  intervals,  will  be 
constantly  stocked  with  larva-destroying  fish  or  will  be  kept  out 
altogether.  The  methods  of  accomplishing  these  results  are 
ditching,  filling  and  diking  and  tide-gating. 

AGRICULTURAL  VS.  ANTI-MOSQUITO  MARSH  DRAINAGE 

In  the  drainage  of  salt  marshes,  as  in  upland  drainage,  there  is  a 
distinction  between  drainage  for  agricultural  purposes  and  drain- 
age for  anti-mosquito  purposes.     As  a  general  rule,  it  may  be  said 

139 


140  MOSQUITO  ERADICATION 

that  drainage  for  agricultural  purposes  is  usually  more  intensive, 
as  well  as  more  expensive,  than  drainage  for  mosquito  control 
purposes. 

"It  seems  clear,"  says  Headlee,1  "that  the  drainage  necessary  to 
prepare  and  maintain  the  marsh  in  condition  for  successful  agriculture 
keeps  the  water-table  so  far  below  the  surface  that  the  original  vegeta- 
tion is  destroyed  and  the  marsh  undergoes  a  large  shrinkage.  In  some 
cases,  this  shrinkage  is  sufficiently  great  to  bring  parts  of  the  marsh 
below  mean  tide  and  to  necessitate  the  use  of  pumps  to  keep  the  water 
far  enough  below  the  surface  of  the  marsh  to  permit  the  growth  of 
crops. 

"In  that  type  of  drainage  necessary  to  eliminate  mosquito-breeding, 
the  water  need  not  be  maintained  at  a  level  lower  than  12  inches  below 
the  surface,  even  during  the  height  of  the  mosquito-breeding  season. 
Indeed,  at  seasons  of  the  year  when  breeding  is  not  occurring,  the  gates 
can  be  opened  and  the  tide  allowed  to  circulate  freely.  It  would  seem 
that  this  type  of  drainage  should  not  destroy  the  salt  marsh  vegetation 
and  that  the  meadow  should  not,  therefore,  materially  shrink.  There 
is  some  evidence  to  show  that,  with  a  proper  system  of  letting  the  water 
on  the  marsh,  the  vegetation  will  not  only  not  be  destroyed,  but  maxi- 
mum crops  of  salt  marsh  hay  can  be  produced." 

DESIGN  OF  SALT  MARSH  DITCHES 

As  a  result  of  the  investigations  of  Dr.  John  B.  Smith,  pioneer 
in  anti-mosquito  work  in  New  Jersey,  it  has  been  found  that  the 
best  type  of  ditching  for  the  usual  salt  marsh  is  a  ditch  10  inches 
wide  by  30  inches  deep,  with  smooth  perpendicular  sides.  This 
depth  normally  reaches  the  bottom  of  the  sod,  and  should  be 
maintained,  except  where  natural  slope  calls  for  a  deeper  cut  to 
insure  the  free  flow  of  the  water.  As  the  upland  is  approached 
and  the  sod  and  underlying  muck  becomes  thinner,  the  depth  of 
the  ditch  is  decreased  accordingly,  neither  sand  nor  subsoil  being 
cut  into,  unless  the  drainage  of  a  pool  or  other  shut-in  area 
requires  it. 

Two  general  plans  of  ditching  have  been  used  in  New  Jersey. 
One  plan,  known  as  the  parallel  system,  calls  for  division  of  the 
territory  to  be  drained  into  districts  on  the  basis  of  possible 
'  outlets,  each  district  to  be  drained  by  parallel  ditches,  sufficiently 
close  together  to  remove  the  surface  water.  The  other  plan, 
known  as  the  pool-connecting  system,  consists  of  running  ditches 

1  "The  Mosquitoes  of  New  Jersey  and  Their  Control,"  New  Jersey  Agri- 
cultural Experiment  Stations,  Bulletin  No.  276,  1915. 


SALT  MARSH  DRAINAGE 


141 


from  one  pool  or  hole  to  another,  and  finally  into  one  or  more 
outlets.  According  to  Headlee,1  the  parallel  plan  is  now  con- 
sidered the  best  practice  in  New  Jersey. 


Hew  Jersey  Aqriculfurat  Cuperimenr  5bHons 

Fig.    100. — Above,  parallel,  and  below,  pool-connecting,  systems  of  salt  marsh 

ditching.      {After  Headlee.) 

Referring  to  the  amount  of  ditching  per  acre  necessary,  on  the 
average,  to  prevent  mosquito-breeding  in  the  New  Jersey  salt 
marshes,  Headlee1  says: 

1  "  Some  Recent  Advances  in  Knowledge  of  the  Natural  History  and  the 
Control  of  Mosquitoes,"  New  Jersey  Agricultural  Experiment  Stations, 
Bulletin  306,  1916. 


142  MOSQUITO  ERADICATION 

"The  estimated  requirements  range  from  90  to  600  lineal  feet  of  10  by 
30  inch  ditching,  or  its  equivalent,  per  acre.  As  a  matter  of  fact,  only 
rarely  is  the  former  figure  practicable,  and  then  under  especially  favor- 
able conditions,  and  never  on  the  New  Jersey  salt  marshes  has  the  latter 
figure  been  reached.  It  seems  probable  that  between  200  and  300 
feet  is  the  real  average.  To  this  must  be  added  an  amount  of 
hole  filling  and  shallow  spurring  which  will  add  about  10  per  cent  to 
the  acre  cost." 

SALT    MARSH    DITCHING    BY    HAND 

The  type  of  ditch  just  described  is  dug  both  by  hand  and  by 
machinery,  the  latter  being  considerably  the  cheaper. 

In  hand  ditching,  the  chief  tools  commonly  used  are  patented 
spades  of  various  types,  these  having  been  found  superior  to 
ordinary  shovels.  There  are  several  different  makes  of  these 
spades  on  the  market. 

In  cutting  the  ditches  by  hand,  it  has  been  found  best  to  remove 
the  sods  in  pieces  about  10  inches  wide  by  6  to  8  inches  thick  by 
30  inches  long.  These  are  heavy  and  not  easily  moved  by  the 
tide;  they  can  also  easily  be  hauled  away  if  desired. 

As  a  general  rule,  numerous  small,  shallow  pools  are  found 
scattered  throughout  the  marsh;  some  of  these  will  not  drain 
readily  into  the  ditches,  but  are  too  small  to  merit  drainage  by 
means  of  spurs.  Such  holes  may  be  filled  with  sods  from  the 
ditches  and  then  smoothed  over,  in  such  manner  as  to  prevent 
formation  of  succeeding  pools.  In  a  year  or  so,  the  grass  will 
grow  over  the  fill  and  the  hole  will  be  entirely  obliterated  as  a 
breeding-place. 

Sometimes,  portions  of  the  marsh  are  so  shut  in  that  opening 
them  to  the  ocean  is  impracticable.  In  these  cases,  the  area  may 
be  trenched  with  the  usual  ditches  to  concentrate  the  water 
which  should  then  be  stocked  with  larva-destroying  fish. 

Particular  care  should  be  taken  in  connection  with  the  outlet 
of  the  ditches.  The  greater  the  tide  drop  and  the  shorter  the 
ditch,  the  greater  is  its  efficiency  and  its  ability  to  keep  clean. 
According  to  Headlee,1  every  ditch  should  have  a  strong  tidal 
outlet,  and  no  ditch  depending  on  a  single  outlet  should  be  more 
than  a  quarter  of  a  mile  long. 

1  "Some  Recent  Advances  in  Knowledge  of  the  Natural  History  and  the 
Control  of  Mosquitoes,"  New  Jersey  Agricultural  Experiment  Stations, 
Bulletin  306,  1916. 


SALT  MARSH  DRAINAGE 
MACHINE  DITCHING 


143 


Several  types  of  ditching  machines  are  used  in  salt  marsh 
mosquito  control  work.  Headlee1  mentions  a  machine  consisting 
of  a  gasoline  power  plant,   equipped  with  revolving  drums  in 


(Photos  by  Atlantic  County,  V.  J.,  Mosquito  Extermination  Commission.) 
Fig.   101. — Above,  left,   front  view  of  the  Eaton  ditches,   showing  plow  in 
distance;  above,  right,  rear  view  of  the  plow,  showing  the  ditch  and  the  way  sods 
are  disposed  of;  below,  a  ditch  cut  by  the  Eaton  ditcher. 

front  and  rear,  and  a  plow  or  trencher  which  makes  the  excava- 
tion. The  power  plant,  mounted  on  planks,  pulls  the  trencher 
forward  by  means  of  a  500  foot  steel  cable;  when  it  becomes 
necessary  to  move  the  power  plant,  an  anchor  is  carried  forward, 
power  is  applied  to  the  other  drum,  which  is  connected  with  the 


144  MOSQUITO  ERADICATION 

anchor  by  another  steel  cable,  and  the  plant  is  drawn  up  to  the 
anchor. 

With  a  machine  of  this  type  and  five  men,  it  is  possible  to  cut 
3,000  feet  of  ditches  a  day,  and,  under  favorable  conditions, 
sometimes  more.  Headlee1  states  that  this  machine  cut  the  cost 
of  ditching  from  2}4  cents  a  lineal  foot  in  1912  to  less  than  1>£ 
cents  in  1916.  At  that  time,  he  states,  the  operating  and 
up-keep  cost  of  ditching  with  this  machine,  as  shown  by  cutting 
hundreds  of  thousands  of  feet,  did  not  exceed  1  cent  a  lineal  foot. 

FILLING 

While  the  method  of  ditching  outlined  above  is  perfectly  satis- 
factory for  the  larger  part  of  the  salt  marsh  areas,  there  are 
certain  sections  of  marsh  that  cannot  be  successfully  treated  in 
this  way.  There  are  areas  which  are  so  shut  in  by  ridges,  fills, 
railroad  grades  and  roadways,  or  so  low-lying,  that  they  may  be 
flooded  by  every  storm  or  extra  high  tide  and  stagnant  water 
remain  on  them  for  weeks.  Again,  it  may  happen  that  on  a 
broad,  open  marsh,  especially  if  the  range  of  tides  be  small, 
there  are  spots  or  pockets  back  near  the  upland  too  low  to  drain 
by  ditching. 

In  such  cases,  the  problem  may  be  solved  either  by  filling  or 
by  diking  and  tide-gating. 

Filling  is  applicable  only  under  certain  circumstances.  Thus, 
it  is  too  expensive  for  general  purposes,  and  is  used  chiefly  in 
cases  where  the  area  to  be  filled  is  small,  where  it  is  very  valuable 
or  where  it  proves  to  be  the  most  convenient  place  for  a  dumping 
ground.  In  making  the  fill,  the  trash  should  be  smoothed  down 
and  levelled  in  such  manner  that  there  will  be  no  opportunity 
for  rain-water  pools  to  form  in  it. 

DIKING   AND    TIDE-GATING   IN    GENERAL 

This  is  the  accepted  method  of  dealing  with  the  areas  described 
in  the  last  section.  It  should  be  recognized  at  the  outset  that 
diking  and  tide-gating  a  given  area  is  strictly  an  engineering 
problem  and  that  it  should  be  handled  as  such.  Failure  to  recog- 
nize this  fact  may  result  in  ineffective  work  and  a  waste  of 
money. 

1  "Some  Recent  Advances  in  Knowledge  of  the  Natural  History  and  the 
Control  of  Mosquitoes,"  New  Jersey  Agricultural  Experimnent  Stations, 
Bulletin  306,  1916. 


SALT  MARSH  DRAINAGE 


145 


Diking  is  necessary,  as  a  rule,  only  when  the  fall  of  the  tide  is 
not  sufficient  to  draw  all  the  water  out  of  the  ditches,  when  the 
drainage  ditches  pass  through  material  of  such  a  nature  that  it  is 
impracticable  or  unduly  expensive  to  keep  them  open  or  when  the 
area  in  question  is  too  low  to  be  drained. 

Diking  implies  the  construction  and  installation  of  tide-gales, 
since  it  is  necessary  that  the  streams  and  ditches  carrying  water 
be  given  an  opportunity  to  discharge.  The  main  purpose  of  the 
diking  is  to  keep  out  all  but  the  very  highest  tides,  so  that  low 
areas  will  not  constantly  be  covered  with  water  and  so  that  the 


Dike 


Fig.    102. —  Method  for  control  of  abandoned  coastal  rice-field. 

water-table  in  the  ground  will  remain  at  a  sufficient  depth. 
Otherwise,  a  comparatively  slight  rain-fall  or  a  high  tide  would 
result  in  pools  that  would  remain  for  days. 

The  dike  should,  as  a  rule,  be  located  from  25  to  50  feet  from 
the  edge  of  the  water,  so  as  to  leave  a  narrow  strip  of  marsh  to 
protect  it  from  wave  action.  It  should  be  sufficiently  high  to 
keep  out  all  but  the  very  highest  of  high  tides,  and  proportion- 
ately wide.  In  constructing  the  dike,  due  allowance  must  be 
made  for  shrinkage. 


CONSTRUCTING  THE  DIKE 

In  constructing  the  average  dike,  mud  and  sods  are  the  chief 
materials.  A  core  ditch,  about  1  foot  wide  and  1  foot  or  more 
deep,  should  first  be  excavated  along  the  center  line  of  the  pro- 

10 


1  Hi  MOSQUITO  ERADICATION 

posed  dike;  the  purpose  of  this  is  to  get  a  good  bond  with  the 
earth.  Sods  are  then  laid  on  either  side  of  this  core  ditch,  and 
the  interval  between  them  tamped  with  mud.  Another  layer 
of  sods  is  then  placed  on  top  of  the  first,  only  a  few  inches  closer 
together,  and  more  mud  tamped  in.  This  procedure  is  continued 
until  the  necessary  height  is  reached.  The  whole  may  then  be 
capped  with  sod  or  plastered  with  mud. 

The  sods  and  mud  generally  are  obtained  from  a  ditch  parallel- 
ing the  inside  of  the  dike.  Sometimes,  this  ditch  receives  the 
flow  from  the  laterals  and  conducts  it  to  a  convenient  tide-gate. 
Sometimes,  a  supply  ditch  is  dug  outside  the  dike,  but,  if  this  is 
done,  care  should  be  taken  that  it  is  properly  connected  with 
adequate  outlets.  In  order  to  prevent  caving,  no  ditch,  either 
inside  or  outside  the  dike,  should  be  located  less  than  8  or  10 
feet  from  the  dike. 

"Some  dikes,"  says  Headlee,1  "have  been  constructed  entirely  with 
mud,  but  always  in  places  where  sod  was  not  available.  In  such 
instances,  the  mud  has  been  scooped  from  a  trench  back  of  the  dike 
(forming  a  ditch  paralleling  the  work  and  giving  useful  drainage),  and 
piled  up  until  a  dike  of  requisite  height,  with  due  allowance  for  shrinkage, 
had  been  built,  which  was  2  feet  wide  at  the  top  and  as  broad  at  the  base 
as  was  demanded  by  the  normal  angle  of  repose.  This  type  of  dike  does 
not  withstand  the  weather  or  the  water  as  well  as  the  sod  type,  but  is 
efficient  if  carefully  looked  after." 

Dikes  vary  in  size,  of  course,  with  the  height  of  the  tides. 
Usually,  along  the  Atlantic  coast,  they  average  from  2  to  4  feet 
high,  2  feet  wide  at  the  top  and  4  to  6  feet  wide  at  the  bottom. 
The  cost  varies  with  the  size.  Fuchs2  reports  construction  of  a 
dike  averaging  2  feet  high,  2  feet  wide  at  the  top  and  4  feet  wide 
at  the  bottom  at  a  cost  of  35  cents  a  lineal  foot. 

To  protect  the  dikes  against  muskrats,  brown  rats  and  other 
rodents  which  may  burrow  through  and  undermine  the  dikes, 
it  is  customary  in  New  Jersey,  to  insert  a  piece  of  chicken  wire 
vertically  in  the  middle  of  the  core  of  the  dike  letting  it  extend 
down  as  far  as  2  to  4  feet  below  the  surface  of  the  marsh. 

1  "Some  Recent  Advances  in  Knowledge  of  the  Natural  History  and  the 
Control  of  Mosquitoes,"  New  Jersey  Agricultural  Experiment  Stations, 
Bulletin  306,  1916. 

2  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


SALT  MARSH  DRAINAGE 


147 


THE  TIDE-GATE  AND  SLUICE-BOX 

At  points  where  streams  or  large  ditches  cross  the  dike,  tide- 
gates  are  required.  There  are  several  types  of  these  devices, 
each  being  applicable  to  certain  conditions.  The  type  most 
commonly    used    includes   a   sluice-box   and    a   swinging   gate. 

The  sluice-box  ordinarily  corresponds  to  a  culvert  and  lies 
at  right  angles  to  the  dike  and  underneath  it.  The  length  is 
determined  by  the  height  of  the  fill  and  the  slope  of  the  filling 
material.  The  cross-section  is  determined,  as  for  culverts,  by 
the  drainage  area,  rain-fall  and  run-off. 

The  swinging  gate  is  a  gate  or  shutter  attached  by  hinges  to 
the  outer  end  of  the  sluice-box  and  so  arranged  that  it  will  readily 
open  with  the  falling  tide  and  readily  close  with  the  rising  tide. 

The  purpose  of  the  sluice-box  and  gate  is  to  discharge  water 
at  low  tide  and  close  up  at  high  tide  in  such  manner  as  to  prevent 
the  tide  from  entering.  In  good  construction,  the  water  in  the 
ditches  and  streams  should  be  maintained  virtually  at  the  eleva- 
tion of  low  tide.  A  heavy  rain  may  result  in  the  accumulation 
of  several  inches  of  water,  but  this  will  be  discharged  at  the  next 
low  tide. 

CONSTRUCTION    OF    SLUICES 

When  the  outlet  of  the  ditch  or  stream  is  deep  enough  to  pre- 
vent the  tide  forcing  back  accumulations  of  mud,  etc.,  into  the 
sluice-box,  it  is  a  good  plan  to  submerge  the  sluice-box  below 
mean  low  tide,  in  order  to  prevent  floating  debris  from  interfering 


Top   of  £>iAc 


Mean    Lev  Tide 


3lolce  - 
box. 


Mean  lens  Tide    _ 


. 


P,l,nj 


5lutce  -bo* 


Fig.    103. — Installation  of  a  sluice-box. 


with  operation  of  the  tide-gate  and  also  to  avoid  periodical 
wetting  and  drying,  which  greatly  shortens  its  life.  If  it  is  not 
submerged,  it  must  be  screened  with  heavy  material. 

Where  excavation  for  the  sluice-box  is  necessary,  a  rude  coffer- 
dam may  be  constructed,  using  earth  for  the  ends,  the  water 
being  bailed  or  pumped  out.     The  box  may  be  set  directly  on 


1  IS 


MOSQ  UI  TO  ERA  DIG  A  TION 


S 


the  earth  bottom,  if  the  bottom  is  hard  and  smooth,  or  on 
piling  driven  under  the  ends  and  middle  of  the  box.  Care  should 
be  taken  in  installing  a  box  to  prevent  any  possibility  of  a  leak 
developing  around  or  under  it. 

Sluice-boxes  are  generally  built  on  the  dry  ground  and  lowered 
into  place;  to  avoid  difficulty  in  this  connection,  it  is  usually 
well  not  to  make  them  too  large.  Should  the  stream  or  ditch 
carry  off  too  much  water  for  one  box,  two  or  more  boxes  should 
be  installed  side  by  side. 


nWii.  ,.">.,  ti% 


Sketch  of  sluice-box  and  tide-gate. 


Sluice-boxes  may  range  in  size  from  a  section  of  1  or  2  square 
feet  and  a  length  of  6  or  8  feet  up  to  a  section  of  15  to  18  square 
feet  and  a  length  of  20  to  30  feet.  They  are  generally  made  of 
2-inch  planks  nailed  to  outside  ribs  at  distances  of  1}^  to  2  feet 
apart.  In  order  to  insure  tight  closing  of  the  gate  or  shutter, 
the  outer  end  of  the  box  is  often  given  a  slight  slope,  usually 
about  1  inch  per  foot. 

According  to  Gies,1  it  is  customary  in  New  Jersey  to  put  a 
coarse  rack  or  screen  at  either  end  of  the  box,  made  of  2  by 
4-inch  lumber,  the  pieces  being  spaced  parallel  to  .each  other  about 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


SALT  MARSH  DRAINAGE 


149 


4  inches  apart,  to  keep  out  heavy  floatage  and  debris,  which 
might  interfere  with  operation  of  the  gate. 

GATE  CONSTRUCTION 

The  gate,  like  the  sluice-box,  is  usually  built  of  2-inch  plank, 
tongue-and-groove  material  being  best.  Sometimes,  two  thick- 
nesses of  plank  are  used.     To  prevent  floating  of  the  gate  on  the 


(a)  O/wiNfiRy  Strap 

HINGE 


il 


a 


c 

Tbp  of  D/*e 


Sluicc  Box 


(  lr)  TlKBER    HlNCE 


65\ 


(c)  Bolt  Eye 

HlNCE 


(d) Screw  Hook-3oi.t 

£YE  HlNCE 


(e.)ScK£\n  Ere -Bolt- 
Strap  H /*/&£■■ 

Fig.   105. — Types  of  hinges  for  tide-gates.      {After  Fuchs,    U.  S.  Public  Health 

Service.) 

rising  tide,  it  is  often  weighted  with  a  piece  of  old  iron  nailed  or 
bolted  on  the  gate  near  the  bottom. 

Many  kinds  of  hinges  for  the  gate  have  been  tried  out.  Fuchs1 
discusses  several  different  kinds  of  hinges  as  follows: 

(1)  "The  common  strap  hinge  does  not  permit  enough  freedom  of 
movement  of  the  shutter  so  it  can  automatically  adjust  itself  against 
the  end  of  the  box.  Also,  it  does  not  permit  the  easy  removal  of  the 
shutter  for  repairs.  (2)  The  rice-field  timber  hinge,  in  which  the 
shutter  is  attached  to  two  vertical  planks,  which  swing  from  a  bracket 
supported  by  posts.  This  type  works  well  and  is  easily  removed,  but, 
being  above  water,  permits  of  tampering  and  rots  quickly.     (3)  Two 


150  MOSQUITO  ERADICATION 

eye-bolts  welded  together,  one  bolted  to  the  box,  the  other  to  the 
shutter.  (4)  Screw  hooks  in  the  shutter,  working  on  eye-bolts  on  the 
box.  This  works  fairly  well.  (5)  Screw  eyes  in  the  shutter,  working 
on  a  bolt  supported  by  a  strap  attached  to  the  box.  By  knocking  out 
the  cotter  pin,  the  bolt  can  be  pulled  out  and  the  shutter  removed." 

Sluice-boxes,  according  to  Fuchs,1  are  the  cheapest  and  most 
satisfactory  type  of  tide-gate,  where  the  stream  is  not  too  large. 
With  labor  at  35  cents  an  hour,  he  gives  costs  of  various  boxes  as 
follows:  A  3  by  4  by  16  foot  box,  placed  several  feet,  under 
water,  $202;  a  2  by  3  by  16  foot  box,  placed  just  below  low  water, 
$33;  a  2  by  3  by  20  foot  box,  placed  just  below  low  water,  $105. 
These  costs  include  both  labor  and  materials. 

SPECIFICATIONS  FOR  LARGE  SLUICES 

Headlee2  gives  the  following  specifications  for  sluices  and  gates 
employed  as  an  outlet  for  a  large  creek  in  New  Jersey,  measuring 
from  75  to  80  feet  wide: 

1.  "All  sluices  shall  have  an  inside  measurement  of  6  by  3  feet,  and 
shall  be  built  of  3-inch  tongued  and  grooved  long-leaf  pine,  free  from 
knots  or  serious  blemish;  they  shall  not  be  shorter  than  15>^  feet  and 
shall  extend  from  the  outside  of  the  dike,  facing  back  under  the  dike. 
These  boxes  shall  be  stiffened  with  4  by  5-inch  ribs,  bolted  at  each 
corner  with  a  3^-inch  bolt,  properly  washered  and  drawn  up  with  a 
satisfactory  nut.  These  ribs  shall  be  placed  around  the  outside  of  the 
box,  fitting  it  closely,  at  distances  of  18  inches  apart.  The  first  and 
last  shall  be  made  flush  with  the  ends  of  the  box.  The  planking  shall  be 
firmly  spiked  to  these  ribs  with  6-inch  galvanized  spikes.  The  top  of 
the  box  shall  be  covered  with  2-inch  long-leaf  pine  spiked  on  the  top  of 
the  ribs. 

2.  "The  dike  shall  be  faced  on  the  river  side  with  plank  piling  for 
120  feet  .  .  .  This  facing  shall  consist  of  3-inch  long-leaf  pine 
planking,  free  from  knots  and  serious  blemish,  not  less  than  14  feet  long, 
driven  in  until  the  top  shall  be  1  foot  below  the  level  given  for  the  top  of 
the  dike.  If  the  tops  of  the  piles  are  splintered,  split  or  broomed  by 
driving,  they  shall  be  cut  off  below  the  lowest  point  of  injury.  In  any 
case,  the  cut  of  ends  shall  not  be  such  as  to  make  length  of  pile  less  than 
provided.     The  top  of  the  piling  shall  be  even  and  bound  together 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 

2  "Some  Recent  Advances  in  Knowledge  of  the  Natural  History  and  the 
Control   of  Mosquitoes,"   New  Jersey  Agricultural  Experiment  Stations 
Bulletin  306,  1916. 


SALT  MARSH  DRAINAGE  151 

by  running  a  3  by  8-inch  stringer  along  the  outside  and  inside  surfaces. 
Each  pile  shall  be  bound  to  this  stringer  by  a  }i-mch  bolt,  which  shall  be 
furnished  with  large  washers  and  a  suitable  nut.  The  opening  for  the 
sluice-boxes  shall  be  made  closely  to  fit  the  boxes.  The  cut  ends  of  the 
piling  above  the  box  shall  be  bound  together  by  3  by  8-inch  stringers, 
which  shall  extend,  one  on  the  inside  and  one  on  the  outside,  from  a  point 
2  feet  beyond  one  edge  of  the  opening  to  a  point  2  feet  beyond  the  oppo- 
site edge  of  the  opening.  These  stringers  shall  be  set  flush  with  the 
cut  ends  of  the  piling,  and  each  pile  which  they  cover  shall  be  bound  to 
them  by  a  J^-inch  bolt,  properly  washered  and  fitted  with  a  nut.  The 
cut  ends  of  the  piling  below  the  box  shall  be  bound  together  in  the 
fashion  above  described. 

INSTALLATION 

3.  "All  sluice-boxes  shall  be  laid  on  two  extra  rows  of  sheet-piling 
composed  of  3-inch  long-leaf  pine  closely  set  together.  The  planking 
shall  be  10  feet  long  and  driven  in  until  the  top  shall  be  9  inches  below 
mean  tide.  The  above  provision  regarding  injury  due  to  driving  and  its 
correction  shall  be  observed  here.  Each  row  of  this  sheet  piling  shall 
extend  4  feet  each  side  of  the  sluice-boxes.  Each  row  shall  be  bound 
together  at  the  top  in  a  fashion  similar  to  that  provided  for  the  dike 
facing,  and  the  piling  at  the  sides  of  the  boxes  shall  extend  up  through 
the  stringers  1  foot,  and  the  rectangle  thus  formed  shall  be  made  closely 
to  fit  the  boxes. 

4.  "At  the  sluice-boxes,  the  inner  side  of  the  dike  shall  be  protected 
by  sheet-piling  wing-walls  made  of  2-inch  long-leaf  pine  without  serious 
blemish,  14  feet  in  length,  driven  in  until  the  top  is  1  foot  below  the  level 
of  the  dike.  The  above  provision  regarding  injury  due  to  driving  and 
its  correction  shall  be  observed  here.  They  shall  be  bound  together  at 
the  top  in  the  same  fashion  as  the  dike  facing,  and  shall  extend  6  feet  on 
each  side  of  the  sluice-boxes. 

5.  "The  river  side  of  each  sluice-box  shall  be  furnished  with  a  7  by 
4-foot  gate  made  of  tongued  and  grooved  white  pine.  It  shall  be  com- 
posed of  two  layers,  the  inside  one  being  made  of  3-inch,  7-foot  planking 
and  the  outside  one  of  2-inch,  4-foot-long  planking,  laid  at  right  angles 
to  one  another  and  firmly  spiked  together.  The  gate  shall  be  hung  in 
front  of  the  opening  with  a  suitable  hinge,  so  that  it  will  readily  open 
with  the  falling  tide  and  readily  close  with  the  rising  tide." 

OTHER   TYPES   OF   TIDE-GATES 

Headlee1  describes  another  type  of  tide-gate,  said  to  be  advan- 
tageous on  account  of  the  greater  ease  with  which  it  can  be  kept 
in  order,  as  follows: 

1  "Some  Recent  Advances  in  Knowledge  of  the  Natural  History  and  the 
Control  of  Mosquitoes,"  New  Jersey  Agricultural  Experiment  Stations, 
Bulletin  306,  1916. 


152 


MOSQUITO  ERADICATION 


"In  this  case,  no  box  is  constructed,  but  heavily-timbered  bulk-heads 
are  built  into  the  stream  until  they  stand  within  approximately  6  feet 
of  each  other.  To  render  their  relation  to  each  other  constant,  they  are 
bound  together  by  heavy  cross-timbers.  At  a  point  half-way  between 
the  two  ends,  a  pair  of  heavy,  6  by  6-inch  well-braced  timbers  are  set 


(Photos  by  California  Corrugated  Culvert  Company) 
Fig.   106. — Battery  of  Calco  culverts  and  gates  in  process  of  installation. 

down  in  such  a  fashion  as  to  form  the  support  and  resting-place  for  the 
tide-gate.  Of  course,  the  joints  between  each  of  the  upright  posts  and 
ths  bulk-head  against  which  it  stands  and  between  the  lower  cross 
timbers  and  the  bottom  are  made  tight. 

"The  tide-gate  is  suspended  from  a  cross-timber  located  well  above 
extreme  high  tide,  and  hangs  against  the  upright  posts.     At  each  end, 


SALT  MARSH  DRAINAGE  153 

the  bulk-heads  are  fitted  with  slots,  in  which  planking  can  be  dropped  to 
form  a  coffer-dam.  The  water  between  the  two  bulk-heads  has  merely 
to  be  pumped  out,  when  these  dams  are  in  place  to  expose  the  gate  for 
repairs  and  the  sluice-way  for  cleaning.  The  top  of  the  sluice-way  thus 
formed  is  left  open." 

Frequently  in  salt  marshes,  areas  are  found  separated  from  the 
main  body  of  water  by  sand-bars.  The  outlets  from  these  areas 
are  channels  through  shifting  sands.  Ordinary  tide-gates 
quickly  fill  up.  A  satisfactory  way  of  dealing  with  such  places, 
according  to  Carroll,1  is  to  construct  a  planked  well  on  the  inner 
side  of  the  bar;  the  well  is  connected  with  the  marsh  area  in 
question  by  a  planked  ditch;  at  the  entrance  of  this  ditch  into  the 
well,  a  tide-gate  is  hung;  the  well  discharges  at  low  tide  through 
a  terra-cotta  pipe  that  passes  under  the  sandy  beach  and  connects 
with  an  iron  pipe  running  out  under  the  water,  so  as  to  deliver  the 
water  from  the  well  a  foot  or  two  below  mean  low  tide.  The  iron 
pipe  is  protected  against  drifting  ice,  etc.,  by  means  of  heavy 
piling  and  cross-timbers. 

For  small  streams  having  a  firm  sub-soil,  a  single  line  of  sheet 
piling,  well  braced  with  large  piles,  is  suggested  by  Fuchs.2 
In  this  case,  the  gate  would  fit  over  a  hole  cut  in  the  piling.  This 
type  of  gate  would  have  the  advantage  of  cheapness  and 
simplicity,  but  it  would  have  to  be  extremely  well-braced 
to  withstand  the  recurring  pressure  at  high  tide,  which  would 
have  the  effect  of  loosening  it,  causing  leaks.  Fuchs2  reports 
that  one  gate  of  this  design  that  he  tried  out  failed  as  a  result 
of  this  tide  pressure. 

THE  CALCO  GATE 

The  Calco  automatic  drainage  gate,  made  by  an  iron-culvert 
company,  has  given  satisfaction  on  several  large  diking  and 
drainage  projects.  This  gate  is  attached  to  one  end  of  a  corru- 
gated iron  culvert,  somewhat  after  the  fashion  that  a  wooden 
gate  is  attached  to  a  sluice-box.  These  gates  are  said  to  be 
sensitive  to  a  difference  of  head  of  less  than  an  inch. 

The  method  of  installing  these  gates  is  similar  to  that  outlined 
for  wooden  gates,  except  that  it  is  sometimes  advisable  to  put 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 

2  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


154 


MOSQUITO  ERADICATION 


a  concrete  core-wall  in  the  fill,  so  as  to  avoid  any  possibility  of 
leakage  along  the  pipe. 

The  following  description  of  a  large  drainage  job,  covering 
5,600  acres  of  Columbia  River  overflow  land  is  compiled  from 
information  furnished  by  the  company: 


(Photos  by  California  Corrugated  Culvert  Covipany) 
Fig.    107. — Installing  a  7-ton  Calco  culvert  and  drainage  gate,  Columbia  River 

project. 

Two  sloughs  were  selected  for  the  drainage  outlets.  At  one 
of  these,  a  battery  of  five  Calco  gates,  attached  to  five  corrugated 
culverts,  6  feet  in  diameter  and  110  feet  long,  were  placed  side 
by  side.     A  row  of  piling,  8  feet  on  centers,  intercepted  each 


SALT  MARSH  DRAINAGE  155 

length  of  culvert  pipe  to  assure  proper  settlement  and  avoid 
misplacement  after  filling  over  the  culverts.  At  the  other 
slough,  a  battery  of  six  gates  and  culverts  was  installed  in  a 
similar  manner.  Owing  to  the  fact  that  the  culverts  at  the  time 
of  placement  would  lie  below  water  level,  it  was  necessary  in 
both  installations  to  lay  the  culverts  with  the  gates  attached. 
Each  culvert  and  gate  unit  weighed  more  than  seven  tons.  Two 
clam-shell  dredges  employed  in  the  dike  work  were  used  to  lower 
them  in  place. 

As  an  auxiliary  proposition,  to  take  care  of  high  water  periods 
and  freshets,  a  pumping  plant  was  provided  at  each  slough. 
Both  installations  of  pumps  and  pipe  lines  were  placed  directly 
over  the  culverts  and  gates. 

To  enclose  the  5,600  acres  against  high  water  required  lYi 
miles  of  dike,  of  an  average  height  of  12  feet.  At  the  culvert 
and  gate  installations,  the  height  of  the  embankment  over  the 
top  of  the  culverts  was  20  feet.  The  total  cubic  yardage  of 
embankment  amounted  to  800,000. 

The  appraised  value  of  the  land  before  improvement  was 
approximately  $50  an  acre,  and  after  improvement,  $250  an 
acre.  The  cost  of  all  diking,  dredging  and  spillways,  was  $60 
an  acre,  leaving  a  net  profit  of  $140  an  acre. 

OPERATION  OF  TIDE-GATES 

Tide-gates,  like  all  other  contrivances,  need  a  certain  amount  of 
attention.  In  addition  to  this,  it  is  imperative  that  they  be 
operated  intelligently. 

Tide-gates  should  be  inspected  at  least  once  a  week  and  pre- 
ferably twice  a  week.  Despite  the  use  of  racks  and  screens, 
there  is  a  certain  amount  of  fine  debris  that  is  almost  bound  to 
enter  the  gate  and  possibly  interfere  with  its  operation.  Even 
though  the  gate  be  below  mean  low  tide  level,  sunken  logs  and 
other  like  objects  frequently  enter  and  lodge  in  the  gate.  These 
must    be   removed,    if   the   gate   is   to   function   satisfactorily. 

There  is  also  another  problem  in  connection  with  tide-gates. 
When  the  gates  are  closed,  fish  cannot  enter  the  marsh  and, 
when  the  fish  supply  gets  low,  there  is  apt  to  be  more  or  less 
mosquito  breeding.  This  is  particularly  the  case  when  sewage 
is  discharged  into  the  marsh.  In  order  to  overcome  such  breed- 
ing, the  practice  in  New  Jersey  has  been  to  raise  the  tide-gates 
for  a  week  or  two  each  month  during  the  period  of  the  lowest 


156  MOSQUITO  ERADICATION 

tides,  throughout  the  summer.     This  allows  the  fish  supply  to 
be  kept  up. 

"Moreover,"  says  Gies,1  "by  raising  the  gates  on  one  side  of  the 
marsh  and  allowing  water  to  enter,  while  keeping  the  gates  on  the  other 
side  of  the  meadow  closed,  except  for  discharge  of  water,  it  is  possible 
to  get  circulation  of  the  water  through  the  ditches  across  the  marsh,  and 
sweep  out  breeding  by  this  mechanical  action.  The  gates  are  all  closed 
during  periods  of  monthly  high  tides  or  storms,  so  the  unusually  high 
tide-water  will  not  back  up  over  the  meadows   .    .    . 

SALT  MARSH  SHRINKAGE 

"There  is  one  other  point  that  has  not  been  touched  on — that  is,  the 
matter  of  meadow  shrinkage,  if  the  gates  remain  permanently  closed. 
Most  salt  marshes  are  composed  of  a  top  layer  chiefly  of  decayed  vegeta- 
tion or  peat  on  a  foundation  of  blue  clay,  mud,  sand,  etc.  The  elevation 
of  the  meadow  surface  is  kept  up  to  a  point  slightly  above  mean  high  tide 
by  the  continuing  growth  and  decay  of  the  salt  grasses,  sedges,  rushes, 
etc.  This  class  of  vegetation  needs  plenty  of  salt  water  to  attain  maxi- 
mum growth,  and,  hence,  if  the  tide-gates  are  kept  continually  closed 
and  the  salt  water  excluded  from  the  marsh,  the  growth  of  the  surface 
vegetation  stops  and  the  spongy  top  layer  of  peat  dries  out  and  begins 
to  pack  down  hard,  and  the  marsh  settles  down  lower  and  lower.  In 
parts  of  Hudson  County,  New  Jersey,  this  shrinkage  has  amounted  to 
several  feet. 

"Finally,  a  point  is  reached  where  the  elevation  of  the  meadow  has 
become  so  low  that  it  can  no  longer  be  drained  by  ditches  or  tide-gates, 
and  it  is  necessary  to  install  pumps,  which  increases  the  cost  of  mos- 
quito control   .    .    . 

"  .  .  .  We  are  keeping  the  tide-gates  open  in  our  own  district,  not 
only  for  about  2  weeks  out  of  every  month  during  the  summer,  but  dur- 
ing the  entire  non-mosquito-breeding  season,  from  November  until 
March.  We  hope,  in  this  way,  to  keep  up  our  marsh  elevation  by  con- 
tinuing our  vegetation  growth,  so  that  we  will  not  be  forced  to  the  extra 
expense  of  pumping." 

PUMPING 

While  small  areas  of  marsh,  so  low  that  they  will  not  drain  at 
low  tide,  may  be  filled,  large  areas  of  this  kind  probably  will 
require  pumping. 

Whether  a  given  area  shall  be  pumped,  what  type  and  what 
capacity  of  pump  shall  be  employed,  what  ditching  must  be  used 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


SALT  MARSH  DRAINAGE  157 

to  bring  the  water  to  the  pump  and  to  take  it  away  arc  engi- 
neering questions  that  can  only  be  decided  by  a  competent 
engineer  after  detailed  study  of  the  particular  problem. 

In  parts  of  Hudson  County,  New  Jersey,  where  the  meadow 
elevation  is  very  near  mean  sea  level  or  lower  and  in  the  low- 
lying  marshes  near  Philadelphia,  Pa.,  very  excellent  systems  of 
pumping  have  been  worked  out.  These  pumps  are  electrically 
driven  and  are  automatic  in  operation,  being  regulated  as  to 
starting  and  stopping  by  a  simple  float,  which  is  raised  or  lowered 
by  the  water  on  the  marsh,  and  starts  or  stops  the  pumps  accord- 
ingly. 

A  12-inch  low-head  centrifugal  electrically  driven  pump, 
installed  in  a  low  area  of  Hudson  County,  N.  J.,  in  1915  at  a 
cost  of  about  SI  ,300,  satisfactorily  drained  a  territory  of  about 
700  acres  at  a  cost  during  the  mosquito  season  of  about  $80  a 
month. 


> 


CHAPTER  VIII 
OILING 

PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK 

Oiling  of  water  surfaces  should  be  considered  as  merely  supple- 
mentary to  drainage  and  other  measures  of  mosquito  control. 
While  oiling  alone  might,  under  certain  circumstances,  suffice, 
the  expense,  over  a  term  of  years,  would  be  excessive.  For 
these  reasons,  oiling  is  usually  confined  to  areas  which  it  is 
impracticable  to  drain,  stock  with  fish  or  otherwise  eliminate  as 
sources  of  mosquito-breeding,  or  else  is  used  temporarily,  pending 
application  of  other  measures. 

The  purpose  of  oiling  is  to  cover  the  surface  of  the  water  with  a 
film  of  oil,  which  kills  larvae  already  present  in  the  water  and 
prevents  further  deposition  of  eggs,  so  long  as  the  film  retains  its 
strength.  The  larvae  are  suffocated,  through  inability  to  pene- 
trate the  film  with  their  breathing  tubes. 

The  necessity  of  oiling  as  a  mosquito  control  measure  will  vary, 
of  course,  with  temperature,  topography,  aquatic  plant  growth, 
presence  of  larva-destroying  fish,  the  nature  of  the  breeding 
areas,  etc. 

WHERE  OILING  IS  APPLICABLE 

The  greatest  virtue  of  oiling,  perhaps,  is  its  applicability  to 
treating  small  rain-water  pools,  too  numerous  to  drain  and  too 
transient  to  stock  with  fish,  yet  often  lasting  long  enough  to 
produce  a  brood  of  mosquitoes.  There  seems  to  be  no  other 
method  so  effective  as  oiling  for  dealing  with  these.  Streams, 
ponds,  swamps  etc.,  may  be  treated  by  drainage  methods  or  by 
means  of  fish;  breeding  in  artificial  containers  about  homes  may 
be  eliminated  by  removing  the  containers  or,  where  necessary, 
screening  them;  but  neither  of  these  methods  is  suitable  for  deal- 
ing with  rain-water  pools. 

Another  large  use  of  oiling  is  to  handle  production  areas  while 
steps  are  being  taken  to  control  them  by  other  means.  Thus, 
the  edges  of  ponds  may  be  oiled,  while  the  process  of  removing 

158 


PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK 


159 


larva-concealing  vegetation  (to  facilitate  control  by  means  of 
fish)  is  being  carried  out,  Also  swamps  may  be  oiled  pending 
construction  of  drainage  ditches. 

APPLYING  THE  OIL 

Ordinarily,  oil  need  be  applied  only  around  the  edges  of  large 
bodies  of  water  and  of  swift-flowing  streams,  since  larvae  rarely 
are  found  in  deep  water  and  are  readily  wafted  away  by  a  swift 
current, 


Fig. 


108. — Oiling  a  grassy  stream  until  vegetation  can  be  removed    for    fish 

control. 


Should  deep  water  be  covered  with  algae,  debris  or  aquatic 
plants,  such  as  water  lily,  closely  matted  grass,  etc.,  breeding  may 
take  place — since  the  larvae  will  be  more  or  less  concealed  from 
the  fish — and  oil  should  be  applied  heavily  over  the  whole  surface, 
unless  other  measures  are  put  into  effect, 

In  slowly  moving  streams,  quiet  pools,  back-waters,  etc.,  are 
often  found  which  may  prove  to  be  breeding  places.  These 
should  be  well  oiled,  unless  other  steps  are  taken  to  prevent 
breeding. 

Also  in  cases,  where  the  flow  of  streams  is  obstructed  by  sticks, 
weeds,  debris  and  other  matter,  the  oil  cannot  be  depended  upon 
to  penetrate  the  mass,  unless  the  whole  surface  is  covered  liberally. 

Ordinarily,  it  is  not  necessary  that  the  film  of  oil  be  thick; 
indeed,  much  oil  is  wasted  in  this  way.  Where  the  water  surface 
is  clean,  a  very  thin  film,  such  as  will  show  a  faint  display  of 
colors  in  the  sunshine  is  sufficient.     Where  the  water  is  foul  or 


160  MOSQUITO  ERADICATION 

covered  with  a  scum,  more  oil  is  required.  The  amount  of  oil 
needed  in  such  a  case  must  be  determined  largely  by  experience, 
since  the  factors  in  the  case  vary  so  much  that  no  definite  state- 
ment on  the  matter  can  be  made. 

KIND  OF  OIL  REQUIRED 

The  oil  used  must  be  thin  enough  to  spread  and  form  a  film, 
since,  unless  there  is  a  uniform  film  over  the  water  surface,  many 
of  the  larvae  will  not  be  suffocated.  Probably  the  best  oil  for 
the  purpose  is  a  light  fuel  oil;  frequently  such  an  oil  can  be  pro- 
cured thin  enough  not  to  require  mixing  with  kerosene;  where 
only  a  heavy  grade  of  oil  is  available,  it  must  be  mixed  with 
enough  kerosene  to  cut  it  thoroughly,  often  from  50  to  75  per 
cent.  Proper  mixing  requires  vigorous  stirring  until  the  mixture 
has  merged  into  a  thin  and  quick-spreading  fluid.  The  main 
practical  considerations  are  that  it  be  thin  enough  not  to  clog  up 
the  sprayer  and  that  it  spread  enough  to  form  a  film. 

Kerosene  alone  is  fairly  satisfactory,  but  it  has  a  tendency  to 
evaporate  too  quickly.  It  is  also  generally  somewhat  more  expen- 
sive than  the  fuel  oil.  Furthermore,  in  using  kerosene,  there 
is  a  tendency  to  use  more  oil  than  is  essential,  as  kerosene  has 
a  secondary  "spread,"  or,  in  other  words,  covers  a  larger  area 
after  an  hour  or  two  than  when  at  first  applied.  A  film  that  is 
almost  too  thin  to  be  measured,  but  which  will  give  an  irridescent 
reflection  in  sunlight,  will  kill  Anopheles  larvae. 

LARVICIDES 

Larvicides  or  substitutes  for  oil  may  be  utilized  to  advantage 
under  some  circumstances.  On  the  other  hand,  however,  it 
should  be  remembered  that  they  are  often  poisonous,  less  effec- 
tive and  more  costly  than  oil.  These  considerations  naturally 
limit  their  profitable  use,  and  LePrince1  suggests  that  they  be 
used  only  under  the  directions  of  boards  of  health  or  health 
officers. 

In  cases  where  rains  are  so  heavy  and  frequent  that  the  oil  is 
likely  to  be  washed  away  before  it  has  time  to  kill  the  larvae,  use 
of  a  larvicide  is  indicated,  provided  conditions  are  such  that  there 
is   no  danger  of  poisoning   cattle  or  other    stock.     Larvicides 

1  "Control  of  Malaria:  Oiling  as  an  Anti-mosquito  Measure,"  U.  S. 
Public  Health  Service    1919. 


PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK 


161 


usually  act  differently  than  oil,  as  they  mix  with  the  water  and 
poison  it,  killing  the  larvae  rapidly. 

Larvicides  also  may  be  used,  with  the  same  proviso  mentioned 
above,  to  treat  large  wind-swept  pools,  where  the  oil  film  is 
blown  off  to  one  side,  before  it  has  time  to  kill  the  larvae.  They 
have  been  used  successfully  in  unpasturecl  swamp  lands,  in 
fire-barrels,  catch-basins,  etc. 

THE  PANAMA  LARVACIDE 

LePrince1  summarizes  the  constituents,  method  of  manufacture 
and  application  of  the  Panama  larvicide — one  of  the  most 
popular — as  follows: 

"One  hundred  and  fifty  gallons  of  crude  carbolic  acid,  containing  not 
less  than  15  per  cent  of  phenols,  are  heated  in  an  iron  tank  having  a 


Fig.   109. — Treating  a  fire-barrel  with  the  Panama  larvicide. 


steam  coil  with  steam  at  50  pounds  pressure;  200  pounds  of  finely 
crushed  and  sifted  common  rosin  are  dissolved  in  the  boiling  acid,  and 
then  30  pounds  of  caustic  soda,  dissolved  in  6  gallons  of  water,  are 
added.  There  is  a  mechanical  stirring-rod  attached  to  the  mixing 
li 


162  MOSQUITO  ERADICATION 

tank.  The  product  is  ready  in  a  few  minutes,  yielding  about  3}i 
barrels.  As  a  mosquito  larvicide,  it  is  used  by  spraying  an  aqueous 
emulsion  (1  part  of  larvicide  to  5  of  water)  over  the  surface  to  be  treated 
and  along  the  margins  of  pools  and  ponds  or  other  mosquito-breeding 
places,  so  that  the  resultant  dilution  of  the  larvicide  has  a  thin,  milky 
opalescence,  representing  approximately  a  dilution  of  1  to  5,000.  A 
1  to  1,000  dilution  kills  the  larvae  more  rapidly,  and  was  used  for  destruc- 
tion of  larvae  in  overflowing  pools,  etc.,  and  where  the  use  of  oil  was 
not  practicable." 

This  mixture,  LePrince  reports,  in  addition  to  being  a  good 
larvicide  and  a  good  disinfectant,  also  proved  to  be  very  useful  in 
destroying  algae.  He  also  found  it  very  useful  for  thinning 
down  heavy  oil. 

OTHER  LARVICIDAL  SUBSTANCES 

Niter  cake  is  a  by-product  of  the  manufacture  of  fertilizer,  the 
active  principle  of  it  being  free  sulphuric  acid.  It  has  been  used 
successfully  for  fire-barrels,  3  or  4  pounds  of  it  being  dropped 
into  each  barrel.  It  has  not  proven  altogether  satisfactory  for 
pools,  catch-basins,  etc.,  as,  it  is  believed,  the  alkalinity  of  the 
soil  often  neutralizes  much  of  the  acid.  As  niter  cake,  where  it  is 
available  at  all,  can  generally  be  obtained  gratis,  it  may  be 
used  profitably  in  artificial  containers,  provided  its  poisonous 
properties  do  not  make  it  objectionable. 

Creosote  has  been  used  successfully  on  a  small  scale,  parallel 
with  the  Panama,  mixture,  as  a  substitute  for  oil.  It  is,  of 
course,  open  to  the  same  objections  regarding  its  poisonous 
properties  as  the  Panama  mixture.  It  is  said  to  be  particularly 
useful  in  protecting  the  edges  of  ponds  and  streams  and  in  places 
where  heavy  verdure  interferes  with  oil  spraying.  Fish  in  a 
flowing  stream  or  in  a  large  body  of  water  are  not  injured  by 
spraying  the  margins  with  creosote,  it  is  reported. 

Water  gas  tar,  a  by-product  of  the  manufacture  of  gas,  con- 
taining phenol,  creosote  and  other  larvicidal  substances,  has  also 
been  reported  as  a  satisfactory  substitute  for  oil.  It  is  applied 
similarly  to  oil.  It  is  said  to  make  a  very  effective  mixture  with 
kerosene  or  with  kerosene  and  fuel  oil.  The  proportions  recom- 
mended by  Bishop1  are:  1  gallon  tar  to  5  gallons  kerosene,  and  1 
gallon  tar  to  2  gallons  fuel  oil  and  5  gallons  kerosene.     He  states 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK  163 

that  this  mixture  does  not  blow  off  to  one  side  of  a  pool  so  readily 
as  does  the  film  of  oil  alone.  Water  gas  tar  can  generally  be 
obtained  at  a  nominal  cost  from  any  water  gas  manufacturing 
plant. 

Paris  green,  diluted  with  a  large  proportion  of  inert  dust  and 
sown  on  the  breeding-place,  much  as  grain  is  sown,  is  reported 
by  Barber  and  Hayne1  to  be  a  satisfactory  larvicide  for  Anopheles 
larvae.  It  is,  however,  useless  for  other  kinds  of  larvae,  since 
they  do  not  feed  on  the  surface.  It  is  reported  that  10  cubic 
centimeters  of  Paris  green  will  suffice  for  at  least  1,000  square  feet 
of  water  surface.  One  part  of  Paris  green  to  100  parts  of  some 
inert  dust,  such  as  road  dust,  seems  to  be  a  favorable  mixture. 
Barber  and  Hayne  report  that  the  minute  quantities  of  Paris 
green  used  appear  to  have  no  effect  upon  top  minnows  or  other 
fish.  They  suggest,  however,  that  the  sower  of  the  poison  always 
keep  to  the  windward  side  of  the  dust  cloud. 

THE  SPRAYER 

The  usual — and,  for  general  purposes,  the  best — method  of 
applying  oil  to  quiet  water  surfaces  is  by  means  of  a  spray-can, 
which  consists  essentially  of  a  container,  a  pump  and  a  spray 
nozzle  at  the  end  of  a  short  rubber  tube.  The  type  which  seems 
to  have  proven  most  satisfactory  for  all-around  anti-mosquito 
work  is  what  is  known  as  the  Panama  knapsack  sprayer.  This 
sprayer  holds  5  gallons  of  oil  and  fits  on  the  back  like  a  knapsack, 
the  pump  being  worked  over  one  shoulder  and  the  spray  tube 
being  directed  by  the  opposite  hand. 

This  sprayer  will  distribute  the  oil  satisfactorily  to  a  distance 
of  20  to  30  feet  from  the  operator — a  valuable  consideration  in 
swampy  or  bushy  areas.  Another  advantage  is  the  fact  that  the 
opening  of  the  nozzle  can  be  adjusted,  so  that  heavier  oils  than 
those  ordinarily  used  may  be  employed.  The  weight  is  so  dis- 
tributed that  the  operator  should  not  easily  become  fatigued. 
The  fact  that  in  walking  over  rough  ground  or  through  bushes, 
the  operator  may  have  both  hands  free  is  also  important. 

Occasionally,  men  who  oil  continuously  for  several  days 
develop  a  sore  back,  caused  by  leakage  of  oil  from  the  spray-can. 
This  leakage  can  generally  be  prevented  by  using  care  in  not 
filling  the  can  too  full  and  by  replacing  any  damaged  washers 
with  good  ones. 

1  Public  Health  Reports,  Dec.  9,  1921. 


l^ 


1G4 


MOSQUITO  ERADICATION 


Several  other  types  of  sprayers  are  also  in  use.     There   are 
various  styles  of  pumps  adapted  to  use  on  barrels,  etc;  the  .barrel 


Fig.   110. — The  knapsack  sprayer. 


Eig-  1520 


Fig.   111. — Barrel  sprayer  mounted  on  a  cart. 

may  be  mounted  on  a  barrel  cart  or,  where  conditions  will  permit, 
on  a  truck  or  wagon  or  on  a  boat.     Considerable  pressure  may 


PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK 


165 


be  developed  with  some  of  these  pumps,  so  that  a  stream  of  oil 
may  be  thrown  50  feet  or  more. 

While  such  spray-pumps  are  very  useful  for  oiling  parts  of 
ponds,  lakes,  etc.,  or  edges  of  rivers  and  streams  or  pools  in  open, 
accessible  territory,  they  lack  the  portability  of  the  knapsack 
sprayer  and  usually  are  of  but  little  value  in  swamp  work  or  in 
areas  where  the  terrain  is  rough  or  timbered. 

For  limited  areas  and  for  use  about  homes,  etc.,  the  oil  may  be 
distributed  by  means  of  a  garden  watering-pot  or  a  small  insecti- 
cide sprayer.  An  oil-soaked  broom  may  be  stirred  into  many 
small  pools  with  good  effect. 

DRIP  CANS 

For  flowing  ditches  or  streams,  "drip-cans"  have  proven  very 
satisfactory.  These  may  be  adapted  to  either  continuous  or 
intermittent  application,  as  the  case  may  require. 

Drip-cans  consist  essentially  of 
a  receptacle  for  oil,  arranged  in 
such  a  manner  that  a  small  quan- 
tity of  the  fluid  drips  from  it  into 
the  water.  This  is  wafted  along 
by  the  current  and  bathes  both 
banks,  also,  if  the  stream  is  in 
good  condition — that  is,  free  from 
obstructions  and  vegetation — 
covering  pools  and  backwaters, 
where  breeding  is  most  likely  to 
take  place. 

Drip-cans  should  be  suspend- 
ed three  or  four  feet  above  the 
stream.  If  heavy  oil  is  used,  this 
elevation  may  profitably  be  in- 
creased, since  the  impact  of  the 
drops  of  oil  on  the  water  breaks 
them  up  and  accelerates  forma- 
tion of  the  film.  The  precaution 
should  be  taken  of  securing  the  drip-can  in  such  manner  that  it 
will  not  be  swept  away  by  high  water. 

In  making  the  drip-can,  the  outlet  ordinarily  should  be  placed 
an  inch  or  so  from  the  bottom  of  the  can,  so  that  any  settleable 
solids  in  the  oil  will  not  cover  up  the  hole.     The  outlet  should  be 


Fig. 


112.— Sketch     of 
drip-can. 


easily-made 


166  MOSQUITO  ERADICATION 

large  enough  to  allow  a  sufficient  number  of  drops  to  fall  to  form 
and  maintain  the  film,  and  no  more,  it  being  borne  in  mind  that 
the  drip  will  decrease  at  night  and  on  cool,  cloudy  days  and 
increase  on  hot,  sunny  days.  Sometimes,  it  has  been  found  that 
a  more  even  flow  is  obtained  by  introducing  a  short,  soft  wick 
into  the  outlet. 

"A  crude,  but  cheap  and  easily  made,  drip-can,"  says  LePrince,1 
"consists  of  a  5-gallon  can,  such  as  is  used  for  shipping  illuminating  oil. 

A  hole  is  made  in  its  bottom  with  a  2  or  3-inch 
Co/*"  round  nail.     A  wad  of  loose  cotton  is  wrapped 

Bo/hm  of  can  •!    • 

around  the  nail  just  below  its  head.  The  nail  is 
then  pushed  through  the  hole  on  the  inside  of  the 
can,  and  ...  oil  is  put  in  the  can,  which  is 
suspended  or  placed  on  a  stand  over  the  ditch. 
Fig"  11.3  —Detail  By  pulling  the  point  of  the  nail  downwards  and 
of  drip-regulating  gently  pushing  it  upward,  the  flow  of  oil  may  be 
device-  decreased  or  increased,  as  desired." 

Frequently,  a  5-gallon  can,  having  a  metal  discharge  tap,  is 
used.  The  tap  can  generally  be  adjusted  to  give  within  a  few 
drops  of  the  number  desired  to  be  discharged  per  minute. 

USE  OF  DRIP-CANS 

The  quantity  of  oil  that  should  be  allowed  to  drip  out  depends 
upon  the  spread  of  the  oil,  the  size  and  alignment  of  the  stream, 
its  grade  and  the  absence  or  presence  of  obstructions  in  it. 
LePrince1  suggests  from  10  to  20  drops  of  oil  a  minute  for  water 
surfaces  1  foot  wide.     He  continues: 

"For  economical  control,  a  trial  should  be  made  at  each  ditch  or 
stream  where  a  drip-can  is  used  to  determine  the  desired  rate  of  flow. 
The  drip-can  should  be  regulated  accordingly.  In  many  cases,  the  drip 
need  be  operated  continuously  for  only  1  or  2  days  of  each  week.  With 
larger  streams,  it  may  be  found  necessary  to  operate  the  drip  con- 
tinuously, day  and  night.  On  long  streams  or  ditches,  it  is  at  times 
necessary  to  use  several  drip-cans.  They  are  then  so  located  that  the 
next  drip-can  is  installed  approximately  at  the  point  where  the  effect 
of  the  drip  at  the  source  disappears. 

"Continuous  dry  weather  may  make  it  become  necessary  to  discon- 
tinue the  use  of  some  drips  or  to  change  their  location.  At  such  seasons, 
pools  will  be  left  isolated  at  the  sides  of  a  stream  and  will  have  to  be 
filled  or  separately  treated  with  oil  by  other  methods.     When  the  stream 

1  "Control  of  Malaria:  Oiling  as  an  Anti-mosquito  Measure,"  U.  S. 
Public  Health  Service,  1915. 


PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK 


167 


stops  running,  the  use  of  drips  is  discontinued,  and  any  water  left  in  the 
stream-bed  is  oiled  with  a  knapsack  sprayer  or  watering-pot. 

"  With  the  best  of  care,  oil  drips  will  clog,  due  to  suspended  solids  or 
heavy  constituents  in  the  oil,  and  must  be  adjusted  as  often  as  necessary. 
The  disadvantage  of  oil  drip-cans  is  that  they  will  not  give  satisfactory 
service  without  proper  attention,  may  become  clogged  or  be  washed 
away  by  floods.  Their  use  is  generally  more  effective  and  economical 
than  the  direct  application  of  oil  by  sprinkler  or  knapsack  sprayer  for 
water  in  motion." 


Fig.   114- — Utilizing  a  drip-can  for  a  flowing  stream.      Note  the  drip-can  fastened 

to  the  rail  to  the  left  of  the  officer. 


OTHER   METHODS   OF   APPLYING   OIL 

Occasionally,  the  moving  water  in  a  ditch  or  stream  may  be 
so  little  that  use  of  a  drip-can  is  not  justified.  In  such  cases, 
a  small  bundle  of  oil-soaked  waste,  placed  at  the  source  of  the 
water  will  often  prove  very  efficacious.  This  will  give  off  a  thin 
film  for  a  week  or  so,  after  which  it  may  be  re-soaked  in  oil  and 
used  again.  This  same  method  may  be  used  to  control  small 
springs,  seepage  water  outcrops,  etc. 

A  somewhat  similar  device,  suited  for  use  in  similar  situations, 
is  a  small  bag  or  box  of  oil-soaked  saw-dust. 

Oil-soaked  saw-dust  has  also  been  used  successfully  in  treating 
ponds,  lakes,  swamps,  etc.,  where  there  is  considerable  floatage 
or  vegetation.  In  such  cases,  it  is  simply  broadcast  over  the 
surface,  somewhat  after  the  fashion  of  sowing  grain. 

There  are  many  other  devices  for  applying  oil  to  water-surfaces, 
several  of  which  distribute  the  oil  from  above  the  water;  others 


1G8  MOSQUITO  ERADICATION 

are  submerged,  the  oil  rising  to  the  surface.  It  is  the  opinion 
of  the  writer,  however,  that  usually  equally  as  good  work  can  be 
done  with  the  devices  already  described. 

FREQUENCY  OF  OILING 

The  frequency  with  which  oiling  should  take  place  depends 
upon  several  different  factors.  Ordinarily,  one  oiling  a  week  or 
every  10  days  is  sufficient,  and  this  was  the  basis  upon  which 
most  of  the  oiling  was  done  in  the  extra-cantonment  work  of  the 
U.  S.  Public  Health  Service  during  the  World  War. 

The  resistance  of  larvae  and  pupae  to  oil  varies  with  the 
different  kinds  of  oil  used  and  with  the  different  genera  of 
mosquitoes.  The  Anopheles  succumb  more  easily  than  the 
Culex.  Frequently,  a  good  film  of  oil  will  kill  virtually  all  the 
larvae  in  a  pool  in  an  hour  or  so.  On  the  other  hand,  the  writer 
has  observed  Culex  still  active  in  a  cess-pool  2  days  after  it  had 
been  well  oiled..  The  oil,  in  this  case,  may  have  been  prevented 
from  forming  a  perfect  film  by  the  floating  matter  in  the  pool 
or  by  the  gas  bubbling  to  the  surface. 

Whatever  the  period  necessary  to  kill  the  larvae  and  pupae 
may  be,  once  they  are  dead,  several  days  must  elapse  before  a 
new  breed  can  reach  the  pupal  stage.  The  exact  time  will,  of 
course,  depend  upon  the  temperature  and  other  factors.  If 
the  weather  is  very  hot  and,  through  early  disintegration  of  the 
film,  new  eggs  are  deposited  promptly,  a  second  brood  of  larvae 
may  appear  within  3  or  4  days  and,  within  a  week,  may  reach 
the  pupal  stage.  Again,  if  the  weather  be  cold  and  cloudy  the 
development  of  the  new  brood  will  be  correspondingly  delayed. 

With  the  above  considerations  in  mind,  it  has  been  suggested 
that  oiling  should  be  done  by  inspection — that  is,  that  there 
should  be  no  set  times  for  oiling,  which  should  be  done  only  when 
it  has  been  determined  by  careful  inspection  that  oiling  is 
necessary.  However,  in  view  of  the  obvious  risks  of  this  method 
arising  from  possible  changes  in  weather  conditions,  possible 
incompetence  or  carelessness  of  inspectors,  etc.,  the  writer's 
experience  has  been  that  best  results  are  obtained  by  regular 
weekly  oiling  of  each  place  that  requires  it — that  is,  has  not 
dried  up  or  has  not  been  treated  effectually  by  some  other  method. 
If  the  project  is  a  small  one,  all  the  oiling  may  be  done  on  1  day 
of  each  week;  if  a  large  one,  it  may  be  necessary  to  have  a  gang 
to  oil  all  the  time,  visiting  each  place  once  a  week. 


PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK  169 

DISTRIBUTION  OF  OIL 

Where  a  large  area  is  to  be  protected  from  mosquito  breeding 
by  means  of  oiling,  it  is  obvious  that  some  convenient  means  of 
transporting  or  distributing  the  oil  must  be  worked  out.  In 
other  words,  there  must  be  some  system  of  getting  the  oil  to  the 
places  where  it  is  to  be  applied. 

Even  in  a  small  town  of  from  5,000  to  10,000  inhabitants, 
the  area  in  which  operations  must  be  conducted  will  cover  several 
square  miles.  Usually,  the  places  that  will  require  oiling  will  be 
found  scattered  over  all  parts  of  this  area.  Obviously,  the  oiler 
cannot  get  his  oil  to  all  these  places  without  some  means  of 
transportation. 

It  has  been  the  experience  of  the  writer  that  procurement  of 
one  or  more  light  trucks,  each  carrying  a  barrel  or  two  of  oil  and 
each  barrel  being  equipped  with  a  faucet,  is  the  best  solution  of 
this  problem  for  the  average  town.  The  driver  of  the  truck 
should  also,  where  practicable,  be  foreman  of  the  oiling  gang. 
Knowing  the  places  which  must  be  oiled,  he  can  disperse  his 
men  in  such  manner  that  he  can  easily  keep  each  supplied  with 
oil,  putting  in  the  intervening  time  in  following  up  and  inspecting 
the  work.  If  the  gang  is  a  small  one,  or  in  case  of  an  emergency, 
he  may  assist  in  the  actual  oiling. 

In  smaller  towns,  where  the  available  funds  will  not  justify 
employment  of  a  truck  for  this  purpose,  a  one-horse  wagon, 
carrying  a  barrel  of  oil  on  the  rear,  will  serve  the  purpose. 

Where  even  this  is  not  available,  barrels  of  oil  may  be  dis- 
tributed at  the  principal  breeding-places  in  such  manner  as  to 
minimize  the  amount  of  walking  required  of  the  oiler.  This 
method  also  was  employed  on  a  very  large  swamp  project  upon 
which  the  writer  was  engaged.  At  each  distributing  point- 
carefully  selected,  so  as  to  obviate  as  much  "toting"  of  oil  as 
possible — a  rack  was  built,  upon  which  4  or  5  barrels  of  oil 
were  left.  A  bung-borer  and  a  faucet  were  also  issued  to  the 
oiler,  so  that,  when  one  barrel  was  exhausted,  he  could  open 
another.  When  the  supply  got  down  to  a  barrel  or  so,  the  oiler 
would  requisition  more  oil. 

STORAGE  OF  OIL 

Whenever  possible,  supplies  of  oil  should  be  stored  in  isolated 
buildings,  and  if  these  buildings  are  fire-proof,  so  much  the  better. 
Laborers  frequently  using  oil  soon  become  careless  with  it,  and 

,  ERSITY  OF 


170  MOSQUITO  ERADICATION 

every  reasonable  precaution  should  be  taken  to  guard  against 
fire.     LePrince1  recommends  a   140°F.  flash-test  oil,  if  the  oil 
is  to  be  stored  near  any  valuable  property. 
LePrince1  continues: 

"Oil  stored  in  unsafe  containers,  as  wooden  barrels  or  improperly 
covered  tanks  near  railroad  tracks,  is  very  apt  to  catch  fire.  Small 
quantities  are  usually  shipped  in  wooden  barrels  and,  if  left  exposed  in 
the  sun,  leakage  occurs  and  danger  from  fire  is  increased.  Provision 
must  be  made  for  fire  protection  and  precautions  taken  to  avoid  spilling 
on  the  ground  at  or  near  the  place  of  storage.  Sufficient  sand  or  loose 
earth  should  be  kept  available  close  to  where  the  oil  is  stored  for  use  in 
extinguishing  a  flame.  Oil-storage  houses  and  faucets  of  storage  tanks 
or  barrels  should  be  kept  locked  when  not  actually  being  used.  No 
smoking  is  to  be  allowed  near  them." 

As  indicated  above,  barrels  of  oil  should  not  be  stored  nor  left 
in  any  place  where  the  sun  can  beat  down  upon  them,  since,  not 
only  is  the  fire  risk  increased,  but  a  very  large  quantity  of  oil  is 
likely  to  be  lost.  The  warmth  of  the  sun  thins  the  oil,  and  some 
of  the  barrels  are  almost  certain  to  leak.  The  amount  of  oil  that 
may  be  lost  in  this  manner  is  surprising. 

In  case  it  is  found  necessary  to  distribute  barrels  of  oil  at 
various  places  throughout  the  area  of  operations,  care  should  be 
taken  to  place  the  racks  in  the  shade  or  else  to  cover  them  over. 

COSTS  OF  OILING 

So  many  factors  enter  into  the  situation  that  it  is  almost 
impossible  to  give  any  rules  to  estimate  the  cost  of  oiling  or  even 
the  amount  of  oil  to  be  used  in  any  project. 

The  weather  is,  perhaps,  the  most  important  factor  in  the  case. 
A  given  area  may  require  twice  or  thrice  the  amount  of  oil  and 
labor  one  year  as  another,  depending  on  the  amount  of  rain-fall 
and  its  distribution.  Topography  is  also  an  important  element, 
as  is  soil-type.  Again,  the  conduct  of  the  campaign  itself  has  an 
effect  upon  oiling;  if  fish  control  and  drainage  are  pushed,  less 
oiling  will  be  required,  and  vice  versa. 

The  following  figures,-  taken  from  five  different  projects  with 
which  the  writer  was  connected,  shows  the  wide  fluctuations  in 
amount  of  oiling  required,  costs  of  oil  and  costs  of  applying  oil, 
even  in  places  of  approximately  the  same  area: 

1  "Control  of  Malaria:  Oiling  as  an  Anti-mosquito  Measure,"  U.  S. 
Public  Health  Service,  1915. 


PLACE  OF  OILING  IN  ANTI-MOSQUITO  WORK 


171 


Pro- 
ject 


Area  in 

square 
miles 


Months 
oiled 


Oil  per 
gallon 


Cost 
of  oil 


Applying 
the   oil; 

hauling 


Total 
cost  for 
season 


Cost  per 
square 

mile  per 
season 


Cost  per 
square 

mile  per 
month 


c 

4 

5 

$0.03 

$       47.52 

$     443.00 

N 

6 

4 

0.03 

64.35 

702.00 

H 

4 

5 

0.05 

176.25 

578. 35 

B 

6 

6 

0.08 

324.86 

1,365.91 

W* 

22H 

$H 

0.16 

4,486.88 

6,425.30 

;   490. 52 

766.35 

754.60 

1,690.77 

10,912.18 


$  122.63 
127.39 
188.65 
281.80 
481.56 


$24.53 
31.85 
37.73 
46.96 

87.56 


*  This  project  was  mostly  swamp  work. 


Wages  on  all  the  above-mentioned  projects  averaged  around 
$2.50  a  day.  Colored  labor  was  employed  principally  on  all  the 
jobs.  The  heading  "Applying  the  oil;  hauling,"  also  includes 
wages  of  foremen. 


CHAPTER  IX 
FISH  CONTROL 

ADVANTAGES  AND  LIMITATIONS 

There  is  no  doubt  that  fish  control,  where  it  is  applicable,  is  one 
of  the  cheapest  and  most  satisfactory  methods  of  fighting  the 
mosquito.  Once  a  natural  breeding-place,  such  as  a  lake  or 
stream,  is  stocked  with  the  proper  kind  of  fish,  about  the  only 


(Photo  by  E.  B.  Johnson,  C.  E.) 
Fig.   115. — Perfect  fish  control  at  a  log  pond  in  Alabama. 

work  required  to  maintain  their  efficiency  is  occasional  cleaning 
of  its  edges.  In  certain  artificial  breeding-places,  such  as  foun- 
tains, underground  cisterns,  etc.,  even  this  is  not  required. 
Even  where  such  cleaning  is  necessary,  it  has  been  the  writer's 
experience,  however,  that,  in  the  long  run,  fish  control  is  often 
cheaper  and  easier  than  oiling  or  ditching.  In  some  places,  such 
as  large,  shallow  ponds,  water-filled  clay-pits,  etc.,  fish  control  is 
about  the  only  solution,  since  often  it  is  not  possible  to  drain  such 
places,  while  weekly  oiling  of  large  water-surfaces  quickly  runs 

172 


FISH  CONTROL 


173 


up  into  money,  even  assuming  that  such  a  procedure  is  prac- 
ticable. Again,  in  the  writer's  opinion,  there  is  no  other  method 
so  effective  for  controlling  breeding  in  shallow  wells,  some  kinds 
of  cisterns,  low  culverts  that  hold  water,  etc.  It  is  also  believed 
that  fish  control,  either  by  itself  or  in  conjunction  with  ditching, 
is  the  best  and  cheapest  method  of  control  for  flowing  streams 
and  ditches,  marshes,  swamps  and  many  other  types  of  mosquito 
breeding-place. 

Fish  control  has  its  limitations,  however.     It  is  not  applicable 
usually  to  rain-water  pools,  since  they  soon  dry  up  and  the  fish 


(Photo  by  E.  II.  Magoon,  C.  E.) 
Fig.    116. — The  bucket  indicates  the  water's  edge.      The  water  area  concealed 
by  the  vegetation  affords  an  ideal   breeding-place,   as  it   is  inaccessible  to  the 
larva  eating  fish,  which  keep  the  rest  of  the  pond  free  from  larvae. 


would  die.  Nor,  as  already  intimated,  is  it  feasible  to  stock  a 
breeding-place  with  fish  and  depend  upon  their  unaided  efforts  to 
eliminate  mosquito  breeding.  On  the  contrary,  they  will  have  to 
be  helped  from  time  to  time. 


HOW  FISH  DESTROY  LARVAE 

Some  interesting  observations  on  the  manner  in  which  fish 
detect  and  destroy  mosquito  larvae  and  on  the  marvelous  self- 
protective  instincts  manifested  by  the  larvae  are  recorded  by 
Hildebrand,1  who  says,  in  speaking  of  Gambusia  affinis: 

"I  took  several  large  Anopheles  larvae  from  dense  vegetation  and 
placed  them  in  open  water  among  top  minnows.     With  one  larva  was  a 

1  "Fishes  in  Relation  to  Mosquito  Control  in  Ponds,"  U.  S.  Bureau  of 
Fisheries,  1919 


174 


MOSQ  UI  TO  ERA  DI  CAT  ION 


small  piece  of  bark.  The  larva  hovered  over  this  piece  of  bark,  and  the 
fish  did  not  detect  it.  When  it  was  placed  in  open  water,  without  the 
least  protection,  the  fish  swam  around  it,  even  'nosed'  it,  while  the  larva 
lay  perfectly  motionless.  At  last,  a  rather  small  minnow  seized  it  and 
swallowed  it.  Placed  another  larva  in  open  water  among  fish.  This 
one  too  lay  perfectly  still,  drifting  like  a  small  stick,  while  fish  swam  all 


Fig.   117.- 


(Photo  by  E.  H.  Magoon,  C.  E.) 
Dipping  up  larvae  concealed  by  dense  vegetation. 


about  it,  nosing  it  a  time  or  two,  but  apparently  not  detecting  that  it  was 
alive  and  something  to  eat.  Finally,  it  drifted  near  a  tuft  of  grass  and, 
with  a  surprisingly  quick  motion,  it  swam  into  the  vegetation.  It  was 
removed  and  placed  in  open  water.  There  it  lay  motionless  for  about 
5  minutes,  when  at  last  it  was  snapped  up  by  an  under-sized  minnow. 
"These  feeding  experiments,  which  were  repeated  many  times,  demon- 
strated that  the  protective  instinct  in  mosquito  larvae  is  highly  devel- 
oped. It  was  shown  many  times  that  the  only  protection  an  Anopheles 
larva  has  from  fish  in  open  water  is  inactivity.     When  the  larva  thus 


FISH  CONTROL 


175 


drifts  along,  fish  evidently  mistake  it  for  an  inanimate  object.  The 
slightest  movement,  however,  on  the  part  of  the  wriggler  apparently 
never  goes  unseen,  and  it  is  instantly  seized  and  devoured  by  the  fish. 
It  often  happens  that  a  mosquito  larva  placed  in  open  water  drifts 
toward  places  of  protection  before  it  is  discovered  by  the  minnows,  and, 
if  no  fish  are  very  near,  it  moves  toward  it  with  a  remarkable  rate  of 
speed  and  quickly  places  itself  over  the  object.'7 

THE  TOP  MINNOW  (Gambusia  affinis) 

The  top  minnow,  Gambusia  affinis  Baird  and  Gerard,  so  far  as 
is  known  at  present,  is  probably  the  best  fish  for  general  anti- 
mosquito  work,  within  its  habitat,  of  any  of  the  North  American 
pisces.  It  is  known  on  the  Atlantic  from  Delaware  to  Mexico 
and  in  the  Mississippi  Valley  from  Illinois  to  Louisiana.  It 
inhabits  both  fresh   and   brackish  water,   while   an   occasional 

*>z  - •.■'•  ?-'* 


Fig.   118. — Gambusia  affinis,  female.     (After  U.  S.  Bun  an  of  Fisheries.) 

straggler  is  taken  in  strictly  salt  water.  This  fish  is  viviparous — 
that  is,  it  gives  birth  to  its  young.  It,  therefore,  requires  no 
special  environment  for  depositing  and  hatching  its  eggs. 

The  female,  which  is  larger  than  the  male,  rarely  measures 
more  than  40  to  45  millimeters  in  length,  although  specimens 
have  been  taken  measuring  as  much  as  65  millimeters  in  length. 
The  average  length  of  the  adult  male  is  25  millimeters.  The 
young,  at  the  time  of  birth,  are  from  8  to  10  millimeters  in  length. 
They  grow  rapidly  at  first,  but  several  months  elapse  before 
they  reach  full  size. 

The  sexes  in  the  young  cannot  be  distinguished  externally, 
but  the  anal  fin  in  the  male  gradually  becomes  modified  into  a 
long,  sharp  process  which  in  the  sexually  mature  fish  serves  as 
an  intromit  tent  organ.  This  process  is  the  characteristic 
identification  mark  of  the  adult  male  Gambusia.  Gravid  female 
Gambusia  may  be  identified  by  a  black  spot  on  each  side  of  the 


176  MOSQUITO  ERADICATION 

abdomen,  above  and  in  front  of  the  vent.  These  spots  increase 
in  size  and,  when  they  join  on  the  ventral  surface,  the  period  of 
parturition  is  near. 

The  young  are  extruded  singly  or  in  twos  and  threes;  the  labor 
may  last  from  an  hour  to  a  day.  The  proportion  of  males  born 
to  females  appears  to  be  about  1  to  8  or  9.  As  many  as  six  broods 
a  year  may  be  born,  each  brood  ranging  from  2  or  3  to  50  or  60. 
A  peculiar  fact  in  connection  with  the  fertilization  of  the  eggs  is 
that,  apparently,  one  copulation  is  sufficient  to  produce  several 
broods. 

This  little  fish  is  one  of  the  hardiest  known.  It  will  live 
equally  well  in  salt,  fresh  or  stagnant  water.     In  foul  or  stagnant 


Fig.    119. — Gamhusia  affinis,  male.      (After  U.  S.  Bureau  of  Fisheries.) 

water,  it  has  been  observed  to  stick  its  mouth  above  the  surface 
from  time  to  time,  making  a  sucking  noise.  The  object  of  this 
action,  it  is  believed,  is  to  get  more  oxygen.  Its  habit  of  swim- 
ming near  the  surface  is  correlated  with  the  fact  that  it  seeks  most 
of  its  food  near  the  surface.  This  habit  is  what  gives  the  fish 
its  value  for  anti-mosquito  work. 

Gamhusia  affinis  is  a  very  voracious  feeder.  One  medium- 
sized  female  has  been  observed  to  eat  as  many  as  165  mosquito 
larvae  in  a  single  .day.  The  young  begin  feeding  a  few  hours 
after  they  are  born,  and  even  at  this  age,  the  young  fish  will 
swallow  a  larva  half  as  big  as  itself. 

THE  BARRED  KILLIFISH  (Fundulus  heteroclitus) 

The  barred  killifish,  also  known  as  the  mud-fish,  pike-minnow 
and  salt-water  minnow,  is  probably  one  of  the  most  effective 


FISH  CONTROL 


111 


of  the  fish  enemies  of  the  salt  marsh  mosquito  in  the  north,  beyond 
the  range  of  Gambusia. 

This  fish  attains  a  length  of  from  4  to  6  inches,  and  is  charac- 
terized by  banded  markings,  rounded  fins,  a  short  head  and 
obtuse  snout,  a  projecting  lower  jaw,  a  convex  tail  and  a  very 
flat  area  between  the  eyes.  While  the  killifish  has  the  faculty 
of  changing  its  color  somewhat  to  approach  its  prey  or  to  escape 


^mKffld|^r^ 

glSSS^ 

^        "'  J 

^5^- 

1  l^i*5  IllliJ 

gjggssy 

ShME^^^ 

Fig.    120. — Fundulus  heteroclitus,  female. 

an  enemy,  the  general  color  of  the  female  is  olivaceous  on  top 
with  a  lighter  belly,  and  the  male  is  darkish  green  on  top  with  a 
yellowish  belly.  Both  male  and  female  generally  have  numerous 
spots  and  markings. 

This   fish  is  oviparous.     The  eggs  are  very  resistant  and,  as 
soon  as  they  are  laid,  they  sink  to  the  bottom  in  the  mud,  which 


^^gj!^^^^^Vf 

¥fjt^*fv%& 

WLfc^ 

5** 

Wmw 

KwtMb 

Hi 

ft*38 

^^^^■^r-  -M^  r         fc^ : 

Fig.   121. — Eundulus  heteroclitus,  male. 

protects  them.  They  hatch  out  in  about  21  days  of  warm 
weather.  The  young  fish  hatches  with  a  yolk  sac,  which  soon 
disappears,  after  which  it  feeds  on  minute  plankton. 

Many  of  the  eggs  are  eaten  by  its  own  kind.  Other  enemies  of 
the  killifish  are  weakfish,  dogfish,  smelt,  striped  bass,  etc.  Man 
frequently  uses  the  young  as  bait. 

The  spring  migration  begins  as  soon  as  the  weather  becomes 
warm,  and  gravid  females  are  found  shortly  thereafter.     The 

12 


178 


MOSQ I  rIT()  ERA  DICA  TION 


spawning  season  lasts  until  late  summer,  the  yearlings  starting 
after  the  elder  ones  finish.  When  cold  weather  comes,  the 
killifish  return  to  deep  water. 

Young  killifish  only  a  few  months  old  have  been  known  to 
devour  large  numbers  of  mosquito  larvae.  Adults  have  devoured 
as  many  as  25  larvae   in  succession.     Stomach  examinations 


dti^b 


Fig.   122. — Fundulus    majalis;   male  above,  female  between  and  young  below. 
(From  Jordan  and  Evermann,  Bull.  47,  U.  S.  National  Mxiseum.) 

have  also  revealed  adult  mosquitoes.     This  killifish  is  also  an 
important  enemy  of  the  green-headed  fly. 

Like  Gambusia,  Fundulus  heteroclitus  is  equally  at  home  in 
salt,  fresh  or  stagnant  water.  It  is  found  in  the  most  insignifi- 
cant pools  and  ditches,  and  has  been  known  to  push  its  way  over 
places  where  there  is  barely  enough  water  to  cover  its  back. 


FISH  CONTROL 


179 


The  ease  with  which  F.  heteroclitus  may  be  artificially  ferti- 
lized and  the  hardihood  of  the  young  embryos  make  the  stocking 
of  pools  and  streams  with  this  fish  an  easy  and  satisfactory  method 
of  mosquito  control. 

THE  STRIPED  KILLIFISH  {Fundulus  majalis) 
This  killifish,  which  may  be  distinguished  from  F.  heteroclitus 
by  its  color,  the  fact  that  its  tail-fin  is  not  so  convex  and  that 
its  average  length  is  an  inch  or  more  greater,  is  also  considered 
as  having  some  value  in  anti-mosquito  work. 


£9ff 


Fig.   123. — Fundulus  diaphanous;  male  above  and  female  below.      (From  Jordan 
and  Evermann,  Bull.  47.  U.  S.  National  Museum.) 

Males  of  this  species  show  vertical  markings  on  the  sides, 
while  the  females  have  more  or  less  horizontal  markings  on  the 

sides. 

This  fish  enters  the  marshes  with  the  tide  and  goes  out  with  it. 
Should  it  get  cut  off  from  the  ocean,  it  will,  according  to  Mast,1 
travel  overland  toward  the  sea  by  flopping  itself  along.  Mast 
also  shows  that  this  fish  seems  to  keep  its  sense  of  direction 
while  traveling  overland,  which  he  attributes  to  internal  factors. 

THE  FRESH-WATER  KILLY   (Fundulus  diaphanous) 

This  species  differs  from  both  of  the  preceding  in  that  its 
tail-fin  is  not  rounded  at  all,  but  is  squarely  cut  off.     The  females" 

1  The  Behavior  of  Fundulus  with  Especial  Reference  to  Overland  Escape 
from  Tide-pools,  Journal  of  Animal  Behavior,  1915. 


180 


MOSQUITO  ERADICATION 


are  olivaceous  with  pale  fins  and  with  sides  marked  with  15 
to  20  dark,  vertical  bands.  The  males  are  a  pale,  olive  color, 
and  have  about  the  same  number  of  white  vertical  bands  on 
their  sides. 

While  this  killifish  is  more  or  less  similar  to  those  previously 
described  in  its  other  habits,  it  sticks  more  closely  to  fresh  water 
than  do  they,  and  indeed  is  rarely  found  in  salt  or  brackish  water. 


s  J  fyf  K<  *3  P  £*  5?  /  V~  « I  feSfi 


P^*« 


'sags 


Fig.    124. — Cyprinodon   variegatus,    male.      {From    U.    S.    Bureau   of  Fisheries.) 


Fig.   125. — Cyprinodon  variegatus,  young.      (From    U.   S.   Bureau  of  Fisheries.) 

THE  VARIEGATED  MINNOW  (Cyprinodon  variegatus) 

This  minnow,  which  occurs  on  the  Atlantic  Coast  from  Cape 
Cod  to  the  Rio  Grande,  ascending  streams  and  inhabiting 
brackish  waters,  is  believed  to  be  of  some  value  in  anti-mosquito 
work,  although  it  subsists  mainly  upon  vegetable  matter. 

The  variegated  minnow,  also  known  as  the  sheeps-head  minnow, 


FISH  CONTROL 


181 


is  very  prolific  and  very  active.  It  is  oviparous,  the  females 
spawning  virtually  the  whole  summer.  The  eggs  are  somewhat 
heavier  than  salt  water.  This  little  fish  is  occasionally  found  in 
strictly  salt  water,  and  foul  water  does  not  seem  to  inconvenience 
it. 

Adult  females  average  about  45  millimeters  in  length;  males 
about  48  millimeters.  Newly-hatched  young  are  about  4  milli- 
meters long. 


Fig.   126. — Lucania    parvia.      (From    Jordan    and    Evermann,    Bull.    47,    U.    S. 

National  Museum.) 


THE  RAIN-WATER  FISH  (Lucania  parvia) 

This  fish,  which  ranges  from  Vy^  to  2  inches  in  length,  is  not  a 
top  feeder,  but  has  been  considered  as  of  some  value  in  anti- 
mosquito  work.  The  males  are  olive  or  light-brown,  the  edges 
of  the  scales  being  darkish;  the  females  have  light,  olive  fins, 
with  no  dark  markings. 

THE  SPOTTED  TOP  MINNOW  (Fundulus  notatus) 

The  spotted  top  minnow  is  found  in  the  Mississippi  Valley 
from  Michigan  to  Louisiana  and  regions  adjacent  thereto.  It 
occurs  only  in  fresh  water.  While  its  value  in  anti-mosquito 
work  is  not  fully  understood,  it  appears  to  be  worthy  of  further 
investigation. 

THE  STAR-HEADED  MINNOW  (Fundulus  notii) 

This  little  fish  closely  resembles  in  habits  and  appearance  the 
spotted  top  minnow.  Its  habitat,  however,  does  not  appear 
to  be  large,  since,  according  to  Hildebrand,  it  seems  to  be  confined 
to  the  Atlantic  slope  from  North  Carolina  to  Florida.  The 
star-headed  minnow  occurs  in  fresh  water  only. 


182 


MOSQUITO  ERADICATION 
OTHER  FISHES 


Several  species  of  sun-fishes  have  been  mentioned  by  different 
writers  in  connection  with  anti-mosquito  work,  but  the  observa- 
tions of  Hildebrand  indicate  that  they  are  of  doubtful  value. 


Fig.   127. — Fundulus  nolii.     {From  U.  S.  Bureau  of  Fisheries.) 


Fig.   128. — Fountain  protected  by  gold-fish. 

Hildebrand1  considers  gold-fish  useful  in  confinement,  although 
probably  of  but  little  value  in  large  bodies  of  water.  Fountains 
stocked  with  gold-fish  and  kept  fairly  clear  of  debris  and  vegeta- 
tion will  rarely  show  any  breeding. 

1  "Fishes  in  Relation  to  Mosquito  Control  in  Ponds,"  U.  S.  Bureau  of 
Fisheries,  1919. 


FISH  CONTROL  183 

Chidester1  has  compiled  the  following  list  of  other  fishes  classed 
as  enemies  of  the  mosquito:  Heterandria  formosa,  Abramis 
chrysolenca,  Mollinesia  latipennia,  Girardinus  poeciloides,  G. 
caudimaculatus,  Haptochilus,  Lucius  americanus,  Cijprinodon 
calaritanus. 

PROCEDURE  IN  FISH  CONTROL 

The  first  procedure  in  connection  with  the  use  of  fish  as  an 
anti-mosquito  measure  is  to  look  over  the  local  fishes  and  ascer- 
tain what  kinds  of  larva-destroying  fishes  there  are  and  which 
will  be  most  suitable  for  the  work  in  hand.  Important  consider- 
ations in  this  connection  are  the  species  of  mosquito-destroying 
fishes  most  numerous  in  the  vicinity  and  the  character  of  the 
places  in  which  they  are  to  be  used. 

In  general,  it  may  be  said  Gambusia  affinis  should  be  used 
wherever  it  may  be  found,  since  for  all-around  work  it  seems 
to  be  superior  to  any  other.  Indeed,  Gambusia  is  frequently 
imported  to  regions  outside  of  its  natural  range  on  account  of  its 
superiority  to  the  native  fishes. 

When  these  matters  have  been  determined,  the  next  step  is  to 
arrange  for  an  aquarium  or  "hatchery,"  so  that  an  abundant 
supply  of  fishes  will  always  be  at  hand  for  stocking  purposes. 
Generally,  a  small,  shallow  pond  can  be  found  for  the  purpose. 
The  pond  should  not  be  so  big,  however,  that  catching  will  be 
difficult.  Nor  should  it,  as  a  rule,  be  located  in  the  bed  of  a 
stream  that  is  subject  to  floods,  since,  in  this  case,  it  is  possible 
that  a  storm  will  disperse  all  the  fish.  Care  should  also  be  used  to 
obtain  an  aquarium  that  is  free  from  bass  and  other  game  fish 
which  feed  on  Gambusia  and  other  minnows. 

On  account  of  the  cannibalistic  habits  of  Gambusia  affinis,  as 
well  as  some  of  the  other  larva-eating  fishes  above-mentioned, 
Hildebrand2  suggests  that  one  corner  of  the  aquarium  be  screened 
off  with  a%6  inch  wire  netting  to  serve  as  a  refuge  for  the  young. 

Steps  should  also  be  taken  to  prevent  local  fishermen  from 
helping  themselves  to  the  minnows  or  other  small  fish  for  use  as 
bait.     It  has  been  found  that  a  little  publicity,  explaining  the 


i 


A  Biological  Study  of  the  More  Important  of  the  Fish  Enemies  of  the 
Salt  Marsh  Mosquito,"  New  Jersey  Agricultural  Experiment  Stations, 
Bulletin  300,  1916. 

2  "Fishes  in' Relation  to  Mosquito  Control  in  Ponds,"  U.  S.  Bureau  of 
Fisheries,  1919. 


184  MOSQUITO  ERADICATION 

purpose  of  the  work  and  perhaps  a  notice  or  two  put  up  at  the 
aquarium,  will  generally  prevent  any  considerable  losses  in  this 
way. 

Fish  for  stocking  the  aquarium,  if  it  is  not  already  stocked  with 
them,  may  generally  be  obtained  in  abundance  from  nearby 
streams  or  swamps.  In  this  connection,  care  should  be  taken  not 
to  draw  too  many  from  one  source,  so  as  to  leave  such  source 
unprotected  against  mosquitoes. 

The  number  of  fish  that  should  be  placed  in  the  aquarium  will 
vary  with  the  size  of  the  aquarium,  the  requirements  of  the  fish- 
control  work  and  the  abundance  of  fish  in  the  vicinity.  It  should 
be  borne  in  mind  that  these  fish,  particularly  Gambusia,  multiply 
with  great  rapidity,  especially  if  those  installed  in  the  aquarium 
include  a  number  of  pregnant  females. 

Should  the  aquarium  be  small  and  the  number  of  fish  therein 
very  large,  it  will  be  necessary  to  feed  the  fish.  Minced  meats 
or  fish,  bread,  corn-meal  and  similar  substances  are  considered 
suitable  for  this  purpose. 

NUMBER  OF  FISH  REQUIRED 

When  the  aquarium  has  once  been  established,  the  work  of 
distributing  the  fish  among  the  places  where  they  are  needed  may 

begin. 

The  first  question  that  arises  in  this  connection  is :  How  many 
fish  are  necessary  in  a  pond,  stream  or  other  breeding-place  in 
order  to  prevent  mosquito  production?  Hildebrand1  answers 
this  question  as  follows : 

"Data  upon  which  a  definite  answer  could  be  based  are  extremely 
difficult  to  obtain,  for  there  are  scarcely  two  ponds  which  offer  identical 
conditions.  The  size  of  the  pond  of  course  must  be  considered;  whether 
or  not  it  is  subject  to  wave  action  is  of  importance;  the  presence  or 
absence  of  vegetation  is  very  important;  and  the  presence  or  absence  of 
enemies  of  Gambusia  (or  other  larva-eating  fish)  must  not  be  overlooked. 
Even  then,  we  can  only  make  a  guess,  for  Anopheline  mosquito  larvae, 
at  least,  breed  much  more  prolifically  in  some  ponds  than  they  do  in 
others  for  reasons  not  understood.   .    .    . 

"It  has  been  shown  .  .  .  that  a  small  number  of  minnows  freed 
badly  infested  pools  of  mosquito  larvae  in  a  short  time;  also  that  they 
destroyed  the  mosquito  larvae  in  ponds  and  kept  the  ponds  free  of  the 

>  "Fishes  in  Relation  to  Mosquito  Control  in  Ponds,"  U.  S.  Bureau  of 
Fisheries,  1919. 


FISH  CONTROL 


185 


aquatic  stages  of  the  mosquito,  unless  protection  was  provided  by  plants 
and  debris.  From  the  knowledge  which  has  thus  been  gained,  we  may 
conclude  that,  if  a  pond  furnishes  little  or  no  protection  for  mosquito  - 
larvae,  a  small  number  of  top  minnows  is  sufficient,  but,  if  it  does 
furnish  protection,  a  much  larger  number  is  desirable.  Anti-mosquito 
work,  however,  may  be  started  with  a  very  small  number  of  Gambusia, 
for  this  fish  multiplies  rapidly.  There  appears  to  be  no  danger  of  over- 
stocking, as  observations  indicate  that  the  more  fish  a  pond  supports  the 
more  certain  are  the  practical  results." 

Precisely  similar  considerations  apply  to  control  of  streams  and 
ditches,  swamps  and  marshes. 


Fig.  129. — A  pool  in  which  fish  control  cannot  be  entirely  effective  on  account  of 

vegetation. 

Underground  concrete  or  brick  cisterns  should  be  stocked 
with  anywhere  from  5  to  50  fish,  depending  upon  the  degree  of 
infestation,  size  of  the  cistern  and  other  conditions.  Fish, 
particularly  Gambusia,  cannot  be  employed  in  metallic,  surface 
cisterns,  since  the  water  gets  too  hot  and  kills  the  fish. 

Low-lying  culverts  that  hold  water  for  any  considerable  time 
should  also  be  stocked  liberally  with  the  fish.  The  writer  has 
found  this  to  be  the  cheapest  way  of  handling  such  culverts. 

Shallow  wells,  where  they  are  abundant,  are  frequently  trouble- 
some breeding-places.  The  writer  has  found  that  satisfactory 
results  follow,  if  from  three  to  five  male  Gambusia  are  lowered 
into  each  of  them.  Such  wells  should  be  inspected  frequently, 
however,  as  it  often  happens  that  users  of  the  wells  haul  out  the 
fish  with  the  water  and,  not  knowing  their  purpose,  do  not  put 


ISC,  MOSQUITO  ERADICATION 

them  back.     When  the  fish  are  let  alone,  however,   they  do 
satisfactory  work. 

DISTRIBUTING  THE  FISH 

In  anti-mosquito  work  in  which  fish  are  used,  best  results  are 
obtained  by  making  some  one  certain  individual  responsible 
for  this  phase  of  the  work.  This  individual  should  be  in  charge 
of  the  collection,  care  and  distribution  of  the  fish  and  of  the  pond, 
marsh  and  stream  cleaning  essential  for  their  advantageous  use. 

Requests  for  fish  made  by  inspectors  or  other  persons  should 
be  at  once  turned  over  to  the  fish  control  foreman  for  action. 
In  order  to  speed  up  distribution  of  the  fish,  it  is  essential  that  he 
have  necessary  facilities  for  his  work.  Among  these  may  be 
mentioned  nets  for  catching  the  fish,  suitable  receptacles  in  which 
to  transport  them  and  means  of  transportation. 

A  very  useful  net  for  collecting  top  minnows  is  a  small  bobbinet 
seine.  A  net  about  12  feet  long  by  3  feet  deep  is  a  good  size. 
Such  a  net,  if  made  of  good  material,  is  light  and  durable,  and  it 
can  be  easily  and  quickly  handled.  A  dip-net,  also  made  of 
bobbinet,  may  be  used  to  advantage  in  places  where  there  are  so 
many  roots  or  so  much  vegetation  that  a  seine  cannot  be  operated. 

Almost  any  kind  of  a  receptacle  for  the  fish  will  do,  but  for 
ordinary  use  in  an  anti-mosquito  campaign,  the  writer  suggests 
a  milk  can,  with  a  cover  of  gauze  or  burlap  substituted  for  the 
metal  cover.  When  about  half-full  of  water,  such  a  can  will 
hold  several  hundred  fish  very  comfortably  and  but  little  water 
will  splash  out  in  ordinary  travel. 

Transportation  may  be  either  by  automobile,  truck  or  wagon. 
For  ordinary  use  in  a  small  town,  the  writer  suggests  a  light 
roadster  with  the  turtle-box  removed  or  a  buggy  or  buckboard. 
Such  a  vehicle  will  comfortably  carry  two  cans  of  fish  on  the  back. 
On  small  jobs,  it  is  likely  that  the  same  vehicle  used  for  carrying 
oil  may  be  utilized  on  certain  days  for  hauling  fish. 

NECESSITY  OF  AIDING  THE  FISH 

Throughout  the  South,  even  in  inland  areas,  it  probably  will  be 
found  that  most  streams,  ponds,  lakes,  swamps  and  similar 
natural  breeding-places  already  are  stocked  with  Gambusia  or 
other  larva-destroying  fish.  In  such  cases,  very  little  new  stock- 
ing will  be  necessary,  but  the  fish  will  have  to  be  aided,  if  best 
results  are  to  be  obtained. 


FISH  CONTROL 


187 


This  aid  must  take  the  form  of  removing  or  otherwise  eliminat- 
ing vegetation  and  other  floating  matter,  which  serve  to  conceal 
the  larvae  from  the  fishes  and  to  prevent  the  fishes  from  reaching 


Fig.  130. — This  formidable  looking  mosquito  breeding-place  offered  quite  a 
problem.  To  have  cleaned  all  the  circumference,  so  as  to  make  fish  control 
practicable,  would  have  cost  a  lot  of  money.  Instead,  it  was  drained  into  a 
large  abandoned  gravel  pit  nearby,  the  edges  of  which  were  already  clean.  In 
this  way,  complete  and  permanent  fish  control  was  obtained  at  slight  cost. 


Fig.   131. — Too  much  vegetation  in  this  pool  for  effective  fish  control. 

the  larvae,  even  though  the  larvae  be  visible.  Just  how  impor- 
tant this  matter  is  is  shown  by  the  following  observation  of 
Hildebrand:1 

1  "Fishes  in  Relation  to  Mosquito  Control  in" Ponds,"  U.  S.   Bureau  of 
Fisheries,_1919. 


188  MOSQUITO  ERADICATION 

"It  is  very  interesting  to  observe  how  quickly  the  top  minnows  learn 
to  follow  the  workmen  engaged  in  cutting  and  raking  vegetation  from 
ponds.  They  soon  become  quite  tame,  and  schools  of  them  work 
almost  under  the  tools  of  the  laborers,  catching  mosquito  larvae  and 
other  insects  as  quickly  as  their  hiding-places  are  destroyed." 

All  aquatic  plants,  however,  do  not  furnish  protection  for 
mosquito  larvae  and  pupae  against  fish,  and  some  even  may  be 
positively  repellent  to  them.  Grasses  and  rushes  and  other 
plants  having  straight  stalks  and  no  submerged  leaves  afford  no 
protection.  Areas  overgrown  with  plants  of  this  nature  have 
been  repeatedly  examined  for  breeding,  but,  if  the  water  was 
stocked  with  mosquito-destroying  fish,  no  larvae  were  found. 
Plants  which  are  likely  to  hang  over  into  the  water  after  maturity 
or  after  freshets,  etc.,  should  be  removed. 

PLANTS  IN  RELATION  TO  FISH  CONTROL 

The  following  plants  appear  to  provide  good  protection,  and 
may  cause  considerable  trouble,  according  to  Hildebrand:1  the 
aquatic  grass,  Hydrochloa  carolinensis;  "coon-tail  moss,"  a 
species  of  Myriophyllum;  and  algae.  Continuing,  Hildebrand1 
says: 

"The  aquatic  grass  grows  in  shallow  water  and  along  the  shores.  It 
has  many  slightly  submerged  leaves,  over  which  the  horizontally 
floating  or  swimming  Anopheles  larvae  hover,  out  of  sight  and  out  of 
reach  of  the  fish.  Wherever  this  plant  occurs,  some  Anopheles  larvae 
are  almost  sure  to  be  present  regardless  of  the  abundance  of  Gambusia. 
It,  therefore,  is  obvious  that,  if  this  plant  occurs  in  ponds  in  which 
mosquito  control  is  desired,  it  must  be  removed.  This  may  be  done 
by  cutting  and  raking  it  or,  if  growing  in  soft  mud,  it  may  be  pulled  up 
by  the  roots. 

"The  plant  locally  (at  Augusta,  Ga.)  known  as  'coon-tail  moss' 
causes  trouble  only  when  it  becomes  detached  and  rises  to  the  sur- 
face. .  .  .  This  floating  mass  must  be  removed  from  time  to  time; 
this  can  best  be  done  on  a  windy  day,  when  it  drifts  inshore. 

"Algae  often  form  mats  which  float  at  or  near  the  surface.  Mos- 
quito larvae,  particularly  Anopheles,  find  protection  from  fish  over  and  in 
these  mats.  Copper  sulphate  was  used  in  the  proportion  of  8  pounds 
to  100,000  gallons  of  water  for  killing  the  algae,  but  this  treatment 
must  be  repeated  frequently.  .  .  .  Oil,  if  used  in  moderate  quantities, 
is  not  injurious  to  fish;  it  can  be  quickly  and  conveniently  applied  and  it 

V'Fishes~in"Relation  to  Mosquito  Control  in  Ponds,"  U.  S.  Bureau  of 
Fisheries,*  1919. 


FISH  CONTROL 


1S9 


is  very  effective,  for  the  algal  pads  act  like  sponges,  retaining  the  oil  and 
making  them  uninhabitable  for  the  mosquito. 

"Water  lilies  do  not,  as  a  rule,  appear  to  furnish  much  protection 
while  growing,  but  some  of  the  plants  die  from  time  to  time.  The  leaf 
then  partly  sinks,  forming  a  depression  over  the  center,  while  the  edges 


Fig.  1 

furnishes 
Service.) 


32. — Showing   growth  of  aquatic  grass  in  corner  of  pond.     Sue 
excellent  protection  for  mosquito  larvae.     (After   U.  S.  Public 


h  grass 
Health 


i 

Ml'                                        *%£*.9*l.  .jiE.    ***** 

an 

-,  J^L 

**7Effv?^i^^ ' 

^^ 

MHGMOE-  ^HpTTfe>f 

^F- 

«   -fin 

4t* 

(U.  S.  Public  Health  Service) 
Fig.   133. — Treating   pond    with    copper    sulphate    to   kill  algae.     Laborer   is 
dragging  a  small  bag  of  the  chemical  through  the  water  by  means  of  a   pole. 


remain  at  the  surface.  The  cup  thus  formed  holds  enough  water  to 
support  mosquito  larvae,  and  with  respect  to  fish  the  larvae  contained 
therein  are  perfectly  safe.  When  the  dead  leaves  drift  inshore  they,  of 
course,  frequently  make  places  inaccessible  to  fish." 


190 


MOSQUITO  ERADICATION 


/ 


The  aquatic  plant,  Naias  flexilis,  which  is  common  in  many 
ponds  and  lakes,  forming  a  thick  growth  over  the  bottom,  nor- 
mally does  not  afford  protection,  as  it  does  not  reach  the  surface 
of  the  water.  During  severe  droughts,  however,  it  sometimes 
reaches  the  surface,  forming  a  dense  mass,  and,  in  such  cases,  it 
makes  excellent  protection  for  larvae  and  pupae. 

he  duck-weed,  Spirodela  polyrrhiza,  sometimes  forms  an 
almost  continuous  cover  over  a  pond  or  a  portion  of  it,  but 
observations  indicate  that  larvae  are  rarely,  if  ever,  found 
therein.  It  is  considered  likely  that  the  covering  is  so  dense  that 
breeding  cannot  take  place. 


Fig.  134. — Picture  showing  how  water-lilies  furnish  protection  for  mosquito 
larvae.  Note  the  water  in  the  leaves  with  turncd-up  edges,  and  how  completely 
the  larvae  therein  are  protected  from  fish. 

The  smart-weed,  Polygonum,  is  another  plant  that  usually  does 
not  afford  protection,  and  which  may  sometimes  be  obnoxious 
to  mosquito  larvae,  according  to  Hildebrand,1  who  says:  "Many 
places  overgrown  with  this  weed  were  repeatedly  examined,  but 
mosquito  larvae  were  not  found,  even  in  apparently  favorable 
hiding-places." 


ELIMINATING   LARVA-PROTECTING   PLANTS 

It  is  evident  from  the  study  of  plants  in  relation  to  fish  control 
that  to  get  full  results,  it  is  necessary  to  remove  from  the  pond 
lake,  stream  or  other  natural  breeding-place  algae  and  other 

1  "Fishes  in  Relation  to  Mosquito  Control  in  Ponds,"  U.  S.  Bureau  of 
Fisheries,  1919. 


FISH  CONTROL 


191 


larva-protecting  plants  or  else  to  treat  them  in  such  manner  as  to 
make  them  obnoxious  to  the  larvae. 

The  first  consideration  is  to  get  rid  of  the  shore  vegetation, 
which  frequently  is  thickest  in  the  shallow  areas  where  mos- 
quitoes are  most  apt  to  breed.  This,  generally,  can  be  done  very 
effectively  with  a  hoe  or  shovel,  the  idea  being  to  leave  a  clean 
edge,  devoid  of  grass,  brush  and  other  debris  which  may  conceal 
the  larvae  from  the  fish. 


(Photo  by  E.  B.  Johnson,  C.  E.) 

Fig.  135. — Breeding  in  this  stream  is  controlled  by  means  of  larva- 
destroying  fish.  Note  the  clean  edges  and  the  cow  helping  to  keep 
them  clean. 

In  some  cases,  this  cleaning  of  the  edges  may  be  accomplished 
more  cheaply  by  lowering  the  water  level  from  6  inches  to  a  foot. 
If  the  water  has  stood  at  its  former  level  for  some  time,  the  new 
shore  line  probably  will  be  quite  clean. 

Often,  there  will  be  some  shallow  coves  or  other  areas  thickly 
covered  with  algae  or  other  aquatic  growths  or  debris,  most  of 
which  will  be  beyond  the  reach  of  the  man  with  the  hoe  or  shovel. 
In  such  cases,  it  may  be  sufficient  to  oil  these  areas  very  liberally 
once  every  week  or  ten  days.  It  should  be  borne  in  mind,  how- 
ever, that  application  of  oil  probably  will  drive  away  the  fish, 
thus  making  it  necessary  to  rely  solely  on  the  use  of  oil  to  control 
the  area. 


192 


MOSQUITO  ERADICATION 


In  oiling  such  growths,  it  sometimes  happens  that  nearby 
portions  of  the  pond,  lake  or  stream  may  be  used  for  bathing  or 
other  purposes  for  which  oil  would  be  objectionable.  In  such 
cases,  the  oil  required  to  deal  with  the  aquatic  growths  must  be 
prevented  from  escaping  to  other  parts  of  the  water  surface. 


1 


Fig.   136.  Fig.   137.  Fig.   138. 

Fig.  136. — Section  of  Ziomsen  subaqueous  saw,  slightly  reduced  in  drawing. 
Fig.  137. — Section    of   improvised  saw  of  "licker-in"  wire,  showing  method 
of  joining. 

Fig.   138. — Section  of  "licker-in"  wire,  slightly  reduced  in  drawing. 


;> 


This  is  best  accomplished  by  running  a  boom  about  the  area  in 
which  it  is  desired  to  confine  the  oil. 

These  booms  may  be  made  of  logs  tied  together  and  to  the  shore 
or  of  boards,  which  are  preferable,  owing  to  their  straightness  and 
lesser  liability  to  become  water-logged  and  sink,  thus  allowing  the 
oil  to  get  out. 


FISH  CONTROL  193 

THE  SUB-AQUEOUS  SAW 

Should  the  aquatic  growths  be  extensive,  it  generally  will  pay 
to  remove  them.  This  may  be  accomplished  by  means  of 
scythes  and  sickles  from  a  boat,  but  the  best  method,  in  most 
cases,  is  by  use  of  a  sub-aqueous  saw.  This  saw,  a  pliable, 
toothed  strip  of  steel,  100  or  more  feet  in  length,  will  cut  many 
kinds  of  aquatic  plants  successfully,  providing  only  that  the  water 
is  not  studded  with  brush  or  stumps.  Probably  the  best  saw  of 
this  kind  is  the  Ziemsen  saw.  a  patented  article. 

A  somewhat  similar,  but  not  so  effective,  a  saw,  may  be  made 
very  cheaply  from  "licker-in"  wire,  which  is  used  in  a  combing 
process  in  cotton  mills  and  which  may  be  purchased  from  mill 
supply  houses.  This  wire  resembles  a  single-edge  saw.  By  ty- 
ing two  wires  together  firmly,  back  to  back,  at  intervals  of  8  to  10 
inches,  with  the  cutting  edges  in  opposite  directions,  a  double- 
edged  saw  may  be  made,  capable  of  cutting  in  either  direction. 
Twisting  seems  to  improve  the  cutting  action.  In  order  to  make 
the  saw  follow  the  contour  of  the  bottom,  weights  should  be 
attached  to  it  at  4  or  5-foot  intervals.  Ropes  should  be  tied  to 
each  end  to  take  hold  of  in  sawing. 

To  use  the  saw,  it  should  be  dropped  to  the  bottom,  the  ropes 
stretching  to  either  shore.  If  the  saw  is  not  more  than  100  feet 
long  or  so,  one  man  at  each  end  can  handle  it;  if  it  be  several 
hundred  feet  long,  however,  two  men  at  each  end  probably  will 
be  required.  If  there  are  many  bushes  or  stumps,  there  should 
be  a  man  ready  in  a  boat  to  disengage  the  sawT  or  lift  it  over  the 
obstacle,  whenever  necessary.  Should  the  span  exceed  the 
length  of  the  saw,  one  end  will  have  to  be  worked  from  a  boat. 
This  is  tedious  and  difficult. 

USING  THE  SAW 

The  sub-aqueous  saw  is  worked  on  the  principle  of  a  cross-cut 
saw,  the  men  pulling  alternately  on  each  end.  The  work  is 
very  fatiguing,  and  the  men  will  have  to  rest  frequently.  Where  - 
there  is  a  current,  it  is  best  to  begin  at  the  downstream  end  and 
work  upward  against  the  current;  this  permits  the  cut-off 
growths,  as  they  rise,  to  float  clown  stream  out  of  the  way,  to 
be  collected  and  hauled  ashore  later.  If  there  is  no  current,  it 
is  preferable  to  cut  in  the  direction  of  the  wind,  if  there  is  any. 

One  annoying  factor  in  connection  with  the  use  of  the  sub- 
aqueous saw  is  the  frequent  breaks,  especially  in  the  case  of  the 

13 


194  MOSQUITO  ERADICATION 

saw  made  from  the  "licker-in"  wire.  The  patented  article 
appears  to  be  made  of  better  steel,  and  the  breaks  are  not  so 
frequent.  However,  they  are  bound  to  occur  with  either  type, 
but  either  can  be  easily  mended  by  overlapping  the  ends  at  the 
break  about  2  inches  and  tying  them  together  with  a  strong 
wire. 

With  labor  at  30  cents  an  hour,  the  cost  of  sawing  probably 
will  average  about  $5  an  acre.  However,  it  is  likely  that  the  cost 
will  vary  with  the  type  of  growth,  condition  of  the  pond  and  many 
other  factors.  In  any  event,  it  would  appear  that  use  of  a  saw 
is  much  cheaper  than  doing  the  work  by  hand. 

In  most  ca^es,  one  or  two  sawings  per  season  should  be  sufficient 
for  most  aquatic  plants.  It  is  believed  that  repeated  sawing 
will  ultimately  destroy  many  of  the  plants. 


CHAPTER  X 
SCREENING 

PLACE  OF  SCREENING  IN  ANTI-MOSQUITO  WORK 

While  screening  cannot,  of  course,  be  considered  a  method  of 
mosquito  eradication,  the  fact  that  it  is  very  useful  under  certain 
circumstances  in  anti-mosquito  work  makes  it  desirable  to  include 
a  chapter  on  the  subject. 

These  circumstances  may  include  cases  where  sufficient  funds 
for  complete  drainage,  oiling  and  fish  control  under  a  general 
community  organization  are  not  available  or  where  the  breeding 
areas  are  too  extensive  to  be  controlled  economically  by  anti- 
mosquito  measures.  Screening  is  particularly  valuable  for 
control  work  in  rural  areas,  where  the  population  is  not  sufficient 
to  warrant  the  expense  usually  involved  in  eradication  work. 

Moreover,  as  it  is  becoming  customary  to  screen  houses, 
anyway,  it  is  well  to  know  what  the  requirements  for  anti- 
mosquito  screening  are,  so  that  the  screening  may  be  as  adequate 
a  protection  against  mosquitoes  as  against  flies  and  other 
insects. 

There  is  no  doubt  that  screening,  where  the  houses  are  in  such 
condition  that  screening  may  properly  be  undertaken  and  where 
the  screening  is  done  carefully  and  thoroughly,  is  one  of  the  most 
effective  methods  of  protection  against  mosquitoes. 

It  should  not  be  inferred,  however,  that  screening  is  a  satis- 
factory substitute  for  mosquito  eradication.  Screening  protects 
only  the  house  screened,  and  people  do  not  stay  in  the  house  all 
the  time.  Unless  eradication  work  is  carried  on,  therefore, 
they  are  subject  to  annoyance  by  mosquitoes  whenever  they 
leave  it.  Furthermore,  screening  rarely  keeps  out  all  mosquitoes. 
If  they  are  abundant  outside,  some  will  always  manage  to  get 
into  the  house. 

It  will  thus  be  seen  that  screening  is  at  best  only  a  partial 
protection.  It  is  only  one  of  the  many  phases  of  mosquito 
control  work. 

195 


196 


MOSQUITO  ERADICATION 


RARITY  OF  GOOD  SCREENING 

Observations  indicate  that  a  very  large  percentage  of  the 
screening  ordinarily  done  is  not  100  per  cent  effective.  This  may 
be  due  to  three  general  reasons,  which  are  as  follows:  (1)  Attempts 
to  screen  houses  that  are  so  poorly  constructed  or  are  in  such 
poor  condition  that  they  cannot  be  effectively  screened;  (2) 
poorly  constructed  or  improperly  fitted  screens  or  screens  having 


(U.  S.  Public  Health  Service) 
Fig.   139. — Tenant  house  in  too  poor  a  condition  to  warrant  screening. 

too  large  meshes;  and  (3)  the  use  of  sliding  or  easily  removable 
screens,  which  frequently  result  in  their  being  left  open  through 
carelessness  or  negligence. 

Tarbett1  reports  that  inspection  of  houses  in  the  vicinity  of 
an  aviation  camp  in  Arkansas  in  1918  revealed  that  not  10  per 
cent  of  the  buildings  were  properly  screened.  In  this  same 
connection,  Carter1  says:  "I  do  not  think  that  2  per  cent  of  the 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


SCREENING  197 

screened  houses  in  the  United  States  are  perfectly  screened.  I 
will  say  this,  that  I  saw  not  a  single  cantonment  that  was  even 
well  screened. " 

ESSENTIALS  OF  GOOD  SCREENING 

The  first  consideration  in  good  screening  is  to  apply  it  only  to 
houses  in  a  state  of  repair  that  justifies  screening.  Therefore, 
in  starting  a  screening  campaign,  the  houses  should  be  carefully 
inspected  and  divided  into  three  classes:  (1)  Those  already  in  a 
satisfactory  condition;  (2)  those  that  can  be  put  in  such  condition; 
and  (3)  those  that  cannot  be  successfully  screened.  The  last 
class  should  not  be  touched,  and  the  second  should  not  be  touched 
cither,  until  the  necessary  repairs  are  made. 

A  No.  16  mesh  cloth  is  sufficient  for  Anopheles  mosquitoes, 
but,  if  protection  against  all  mosquitoes  is  desired,  the  cloth 
should  be  at  least  18  meshes  to  the  inch,  as  Aedes  calopus  can 
pass  through  a  No.  16  mesh.  Varying  conditions  may  demand 
the  use  of  different  kinds  of  screening  material,  but,  for  adequate 
protection  against  all  mosquitoes,  nothing  less  than  18  meshes 
to  the  inch  should  be  considered,  or,  if  a  screening  material  of 
less  than  this  be  used,  it  should  be  painted. 

A  third  essential  is  that  the  work  be  carefully  done.  This 
means  that  certain  rules,  evolved  by  experience,  should  be 
followed,  and  that  the  work  should  be  executed  with  skill  and 
care. 

A  fourth  essential  is  that  no  opportunity  for  tampering  with 
the  screening  be  afforded.  This  means  that  no  easily  removable 
screens  be  used.  As  already  pointed  out,  if  screens  of  such  type 
are  employed,  they  will  be  sure  to  be  left  open  occasionally. 

Finally,  every  opening  in  the  house  should  be  screened.  It 
will  not  do  much  good  to  screen  the  doors  and  windows,  if  the 
chimneys  are  left  unprotected  and  open  spaces  are  left  elsewhere. 

SCREENING  OF  DOORS 

Since  screening,  like  the  proverbial  chain,  is  only  as  effective 
as  its  weakest  point,  especial  attention  should  be  paid  to  this 
weak  point,  which,  in  most  cases,  is  the  door.  This  is  because  it 
is  the  one  movable  section  most  frequently  used  and,  therefore, 
is  most  subject  to  the  carelessness  of  the  people  who  use  it. 

As  mosquitoes  are  prone  to  congregate  on  the  sheltered  or 
leeward  side  of  a  building,  rather  than  on  the  windward  side,  it  is 


1<)S 


MOSQUITO  ERADICATION 


well,  if  a  door  on  that  side  is  frequently  used,  to  build  a  little 
vestibule  of  screen  material  about  it.  Prolonged  observation 
indicates  that  mosquitoes  are  bound  to  get  in  most  single  doors, 
even  though  they  be  opened  only  for  a  moment.  However,  if 
there  is  a  vestibule  in  front  of  the  door  proper,  so  that  the  second 
screen  door  is  not  opened  until  the  first  is  closed,  the  chances  of 
entrance  by  mosquitoes  are  very  much  decreased. 


■pilii 

*^|] 

1*9*                 ■    . 

I  j 

1     ^^___       B  i  j 

Fig.  140. — Vestibule  to  porch  with  double  screen  doors,  shown  on  right  and 
extreme  left,  the  outer  doors  being  at  the  left.  The  screening  material  does 
not  show  up  very  plainly. 

Screen  doors  should  always  open  outward,  else  the  mos- 
quitoes which  settle  on  them  will  be  driven  into  the  house  when- 
ever they  are  opened,  particularly  when  a  person  enters  the  house. 
This  is  a  point  that  should  be  kept  in  mind  at  all  times. 

"When  the  door  of  entrance,"  writes  Carter,1  "is  at  the  top  of  a 
flight  of  steps,  no  landing  intervening,  it  should  be  so  placed  that  the 
edge  of  the  door  opposite  the  hinge  comes  as  near  the  middle  of  the 

^'Anti-malarial  Measures  for  Farm-houses  and  Plantations,"  U.  S. 
Public  Health  Service,  1919. 


SCREENING  199 

length  of  the  step  as  may  be.  This  may  be  done  by  having  folding  doors 
one  best  to  stay  fastened,  or  by  moving  the  whole  single  door  to  the  left 
and  fill  in  the  space  to  the  right  by  screening.  The  reason  is  that  one 
always  goes  up  about  the  middle  of  the  steps,  and,  if  the  door  opens  from 
the  ends  of  the  steps,  the  person  entering,  after  beginning  to  open  the 
door,  steps  down  a  couple  of  steps  so  as  to  get  out  of  its  way,  thus  open- 
ing the  door  more  widely  and  holding  it  open  longer  than  advisable." 

SOME   GENERAL   RULES 

The  following  general  rules  in  regard  to  construction  and 
installation  of  screen  doors  are  given  by  Snidow:1 

1.  "To  prevent  warping,  the  frame  should  be  made  of  substantial, 
carefully  selected,  light-weight  material,  well-braced  with  iron  brackets 
at  the  corners.  In  order  to  add  a  double  protection  against  sagging,  a 
wire  support  should  be  drawn  diagonally  across  the  lower  half.  This 
may  be  accomplished  by  use  of  a  double  wire  attached  loose,  then 
tightened  with  a  turn-key  until  the  desired  tension  is  reached. 

2.  "The  section  of  screen  wire  covering  the  frame  should  be  cut 
sufficiently  large  to  allow  a  lap  of  Y±  inch  all  the  way  around,  and  should 
be  tacked  on  firmly  with  tacks  not  more  than  3  inches  apart.  After- 
wards, molding  strips  should  be  nailed  on,  covering  edges  of  wire  and 
tack  heads. 

3.  "The  lower  half  of  the  door  frame  should  be  covered  on  the 
inside  with  a  reinforcing  section  of  the  so-called  hardware-cloth,  a 
coarse,  substantial  wire  screen  with  about  a  quarter-inch  opening 
between  the  meshes.  This  will  protect  the  bottom  panel  of  the  door 
from  kicks  and  the  carelessness  of  children. 

4.  "A  light  strip  of  wood,  about  3  inches  broad,  should  be  nailed 
across  the  door  frame  at  about  the  height  of  a  man's  shoulders.  This  is 
to  push  against  when  opening  the  door. 

•     5.  "A  satisfactory  spring  should  be  used  to  insure  the  door  remaining 
tightly  closed  against  the  battens  when  not  in  use. 

6.  "Two  hooks  or  catches  should  be  provided,  one  about  half-way  up 
to  the  top  section  of  the  closing  side  of  the  frame,  and  the  other  near  the 
bottom.  The  top  catch  may  be  used  alone  during  the  day,  but  at  night 
both  should  be  fastened.     This  will  help  to  prevent  warping. 

7.  "In  fitting  screen  doors  in  the  door  frames,  no  attempt  at  edge- 
fitting  should  be  made.  The  door  should  be  made  to  fit  against  a%-inch 
batten  all  the  way  around  the  inside,  and  sufficient  space  should  be 
allowed  around  the  edges  and  the  frame  for  the  door  to  swell  in  wet 
weather  without  scraping  at  the  bottom." 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


200 


MOSQ UI  TO  ERA  DI CA  TION 


The  writer  would  supplement  the  provision  for  reinforcing  the 
lower  half  of  the  door  (No.  3)  by  adding  a  light,  wooden  "kick- 
board,"  similar  to  the  "push-board"  mentioned  in  No.  4,  to 
receive  the  kick  with  which  many  persons  open  screen  doors. 

Almost  any  substantial  hinge  will  do.  Spring  hinges,,  the 
springs  of  which  can  be  adjusted  from  time  to  time,  have  been 
found  advantageous  by  the  writer,  as  they  render  unnecessary 
the  separate  springs  commonly  used,  which,  as  a  rule,  soon 
weaken  if  a  door  is  used  very  much. 

SCREENING  OF  WINDOWS 

Many  of  the  considerations  that  are  mentioned  above  in 
connection  with  the  screening  of  doors  also  apply  to  screening  of 


Fig.  141. — Close-up  view  of  a  window  screen.  This  screen  hangs  from  the 
top  and  is  drawn  up  tightly  against  the  battens  on  the  sides  and  the  sill  on  the 
bottom  by  a  hook  fitting  in  a  ring  attached  to  the  inside  of  the  sill. 


windows.     Probably  the  most  important  of  these  is  that  relating 

to  making  the  frame  of  the  screen  fit  tightly  up  against  battens. 

Probably  the  best  type  of  screening  for  windows  is  that  in  which 

the  top  of  the  frame  is  hinged  to  the  batten  over  the  window  with 


SCREENING  201 

small  metallic  fasteners.  The  parts  of  the  fasteners  attached  to 
the  screen  frame  fit  into  the  parts  on  the  window  batten.  A 
hook  at  the  bottom  of  the  screen  frame,  connecting  with  a  ring  in 
the  window  ledge,  draws  the  frame  of  the  screen  tightly  against 
the  window  battens  on  the  sides  and  top  and  the  ledge  on  the 

bottom. 

When  there  is  no  suitable  batten  or  when  the  window  frame  is 
in  bad  shape,  as  is  frequently  the  case  in  negro  cottages,  it  prob- 
ably is  best  to  tack  the  screen  material  over  the  whole  window. 


Fig.  142. — Screened  porch  at  cantonment.  The  screening,  which  runs  up 
and  down,  is  supported  by  2  by  4  timbers.  The  edges  of  the  screening  are 
covered  with  molding  strips. 

Molding  strips  then  should  be  nailed  over  the  tack  heads  around 
the  window  opening. 

Iron  brackets  should  be  used  to  strengthen  the  corners  of 
window  screens  as  well  as  of  door  screens. 

SCREENING  OF  PORCHES 

This  may  be  done  in  any  way  that  will  result  in  an  effective 
job.  The  screening  may  be  put  on  either  horizontally  or  ver- 
tically. In  either  case,  the  framing  for  the  screen  should  be 
firm  and  substantial,  the  various  supports  being  placed  at  such 
intervals  that  there  will  be  plenty  of  lap  for  tacking  on  the  wire. 
After  the  screening  is  firmly  in  place,  the  edges  should  all  be 
covered  with  molding. 

One  point  that  should  not  be  overlooked  in  porch  screening  is 
the  importance  of  not  leaving  any  open  spaces  where  screening 


202 


MOSQUITO  ERADICATION 


connects  with  a  sided  or  weather-boarded  surface.  The  best 
way  of  doing  this  probably  is  to  cut  the  support  to  fit  the  surface. 
If  this  is  not  practicable,  the  resulting  spaces  should  be  filled  up 
with  paper  pulp,  pieces  of  wood  or  other  material. 

Sometimes  the  nailing  of  a  strip  along  the  outer  edges  of  the 
porch  as  a  support  for  the  bottom  of  the  screen  wire  may  interfere 
with  the  draining  off  of  rain-water  that  may  be  blown  in  on  the 
porch  during  storms.  One  way  to  provide  for  this  contingency 
is  to  bore  a  few  holes  in  the  floor  just  inside  the  bottom  strip  and 
tack  small  pieces  of  screening  material  over  or  underneath  them. 

SCREENING  OF  CHIMNEYS  AND  FIRE-PLACES 

When  the  house  is  provided  with  fire-places,  screens  are 
required  either  at  the  tops  of  the  chimneys  or  over  the  openings 


Fig.   143.- 


([/.  S.  Public  Health  Service) 
-Chimney  protection. 


of  the  fire-places.  Observations  indicate  that,  unless  the  chimney 
or  fire-place  is  screened,  mosquitoes  will  descend  into  the  house 
by  this  route  in  abundance. 

As  the  fire-places  are  usually  not  used  much  during  the 
mosquito  season,  it  has  been  found  that  screening  the  chimney 
is  often  the  easiest  way  of  handling  this  matter.  A  section  of 
screen  wire  is  placed  over  the  chimney  and  held  in  position  by  a 
tier  of  bricks  around  the  edge  of  the  top. 

As  soot  soon  fills  the  meshes  of  the  wire,  if  the  chimney  is  used, 


SCREENING  203 

it  will  be  found  advisable  in  most  cases  to  remove  the  screen 
from  the  chimney  as  soon  as  cold  weather  comes. 

Should  it  be  desired  to  screen  the  fire-place  instead  of  the 
chimney,  this  may  be  done.  Probably  the  best  way  of  doing 
this  is  to  make  the  frame  of  the  screen  fit  exactly  the  fire-place 
opening.  If  the  fire-place  is  screened  instead  of  the  chimney,  all 
stove-pipe  openings  in  the  chimney  should  also  be  closed. 

In  some  sections,  it  is  customary  to  bore  a  hole  in  the  floor  to 
permit  the  drip  from  the  ice-box  to  escape  through  to  the  ground. 
In  such  cases,  mosquitoes  may  enter  the  house  through  these 
holes.  The  best  way  to  prevent  this  is  either  to  divert  the  drip 
to  the  sewer  by  means  of  a  pipe  or  else  to  close  the  hole  and  put 
a  pan  under  the  ice-box,  emptying  it  whenever  necessary. 

THE  LIFE  OF  A  SCREEN 

The  life  of  a  screen  ordinarily  depends  upon  two  things — the 
material  of  which  it  is  made  and  the  care  it  receives. 

Probably  the  best  material  for  screens  for  all-round  use  is 
bronze  or  copper.  This  material  will  last  a  life-time,  unless 
torn  by  accident.  It  is  so  expensive,  however,  that  but  little 
bronze  or  copper  screening  is  seen  today. 

The  material  most  commonly  used  is  a  galvanized  iron.  The 
life  of  this  type  of  screen  depends  upon  its  care  and  treatment. 
Ordinarily,  away  from  the  sea-coast,  this  type  of  screening  should 
last  several  years— from  4  or  5  to  10  or  11.  Carter1  states  that 
the  screening  of  the  U.  S.  Marine  Hospital  at  Baltimore— a 
so-called  rustless  iron— put  on  in  1903  did  not  require  renewal  until 
1914.  This  screening  was  not  painted  until  the  fourth  year,  and 
then  was  painted  with  a  very  thin  coat  every  second  year.  The 
writer  has  observed  galvanized  iron  screening,  put  on  in  1917,  in 
very  good  condition  late  in  1921,  and  it  had  not  been  painted  at 

all. 

Judicious  treatment  will  undoubtedly  greatly  prolong  the  life 
of  a  screen.  It  is  reported  that  an  application  of  banana  oil  each 
season  gives  very  good  results.  The  ordinary  treatment,  how- 
ever, is  painting,  a  very  thin  coat  being  applied  every  second 
year  or  so. 

Torn  wire  screening  may  be  repaired  by  placing  a  small  piece 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 


204  MOSQUITO  ERADICATION 

of  screening  over  the  torn  opening  and  sewing  it  fast  with  a 
strand  of  thin  wire. 

SCREENING  NEAR  THE  SEA-SIDE 

The  economical  screening  of  houses  close  to  the  sea  and  exposed 
to  the  extreme  salt  atmosphere  of  the  ocean  is  a  problem.  Houses 
a  few  hundred  yards  from  the  water  are  not  so  difficult,  but  no 
metal  screen  seems  to  last  very  long  on  houses  close  to  the  salt 
water.  Painting  does  not  alway  appear  to  help  matters,  and,  in 
some  cases,  seems  to  cause  more  rapid  deterioration. 

Ordinary  cloth  screens  are  objectionable  on  account  of  their 
interference  with  ventilation,  their  sagging  and  the  facility  with 
which  they  catch  and  hold  dust,  etc.  Snidow,1  however,  recom- 
mends a  type  of  cloth  screen  which  has  a  hard,  waxed  surface, 
similar  to  that  of  wire. 

Carter1  reports  that  at  the  Chandelcur  Islands  double  bob- 
binet  lasted  a  full  season,  while  iron  screen  material  endured  only 
three  months. 

CONDUCTING  A  SCREENING  CAMPAIGN 

In  cases  where  it  has  been  decided  to  initiate  a  screening 
campaign  in  a  community,  the  best  practice  seems  to  be  more  or 
less  as  follows: 

1.  The  area  should  be  carefully  surveyed,  every  house  being 
visited  and  classed,  as  described  earlier  in  the  chapter.  Once  this 
is  done,  some  idea  of  the  cost  of  the  campaign  can  be  obtained. 

2.  The  next  step  should  be  to  decide  upon  the  best  way  of 
doing  the  work — that  is,  whether  it  will  be  preferable  to  let  each 
house  owner  screen  his  own  premises  or  to  have  all  screening 
done  by  the  director  of  the  campaign.  The  writer  strongly 
recommends  the  latter  method,  since,  in  this  way,  large  savings 
are  made  possible  by  consolidated  buying  and  by  having  a 
standardized  procedure,  and  the  work  will  be  done  better  and 
more  uniformly. 

3.  Owners  of  properties  that  require  repair  prior  to  screening- 
should  be  given  a  certain  length  of  time  in  which  to  make  the 
repairs.  Those  not  worth  repairing  should  be  ordered  vacated, 
if  practicable,  and,  if  not,  nothing  should  be  done  toward  screening 
them,  as  the  imperfect  results  would  only  tend  to  discredit  the 
work. 

4.  Once  the  materials  are  procured,  transportation  obtained 

x" Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1910. 


SCREENIXC;  205 

and  construction  gangs  organized,  the  work  should  be  carried  on 
systematically,  street  by  street,  or  block  by  block.  Careful  cost 
records  should  be  made. 

5.  A  system  of  monthly  inspection  should  be  organized  to  see 
that  the  screening  is  maintained  in  good  condition. 

VALUE  OF  SCREENING 

That  screening,  if  properly  done,  is  very  effective  in  reducing 
morbidity  and  annoyance  occasioned  bjr  mosquitoes  is  certain. 
Shaw1  reports  that  at  Lake  Charles,  La.,  the  malaria  rate  of 
screened  houses,  as  ascertained  by  history  index,  was  50  per  cent 
lower  than  in  unscreened  houses. 

The  St.  Louis  &  Southwestern  Railway  in  1917  began  screen- 
ing the  box  cars  in  which  its  bridge  and  building  gangs  sleep. 
The  following  table2  shows  the  remarkable  falling  off  in  the  rate 
of  hospital  admissions  for  malaria  following  the  screening: 

1915  1916  1917  1918 

Hospital  admissions  for  malaria 87  74  37  11 

An  interesting  demonstration  involving  screening  was  carried 
out  on  a  number  of  plantations  near  Lake  Village,  Ark.,  in  1916 
by  the  U.  S.  Public  Health  Service  and  the  International  Health 
Board.  Thirty-three  houses  were  screened  at  a  cost  of  $14.59 
per  house  or  SI. 76  per  capita.  The  incidence  of  malaria,  as 
revealed  in  blood  examinations  in  May  and  December,  1916, 
both  of  the  screened  group  and  of  a  control  unscreened  group,  is 
shown  in  the  following  table.3 


May 

December 

Screened  group,  per  cent  infected 

11.97 

21.84 

3.52 

Unscreened  group,  per  cent  infected 

19.23 

COST  OF  SCREENING 

While  the  cost  of  screening  varies,  of  course,  with  the  size  of 
the  house  and  the  number  of  doors,  windows,  porches  and  chim- 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 

2  Transactions  of  the  First  Annual   Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Sendee,  1919. 

'"Malaria  Control,  A  Report  of  Demonstration  Studies,"  U.  S.  Public 
Health  Service,  1917. 


20(3 


MOSQ  VI  TO  ERA  DICA  TION 


nej^s  or  fire-places  in  it,  the  cost  of  screening  an  ordinary  four- 
room  or  six-room  house  should  not,  as  a  rule,  much  exceed  $25 
to  $50,  if  ordinary  galvanized  iron  screening  material  is  used. 
An  itemized  table  of  the  cost  of  screening  31  houses  at  Kress, 
Va.,  in  1918  is  given  by  Snidow.1  On  this  job,  Snidow  says,  it 
was  unnecessary  to  screen  any  chimneys.  Galvanoid  screen 
wire,  used  in  the  work,  cost  $3.50  per  100  square  feet,  wholesale. 
The  table  follows: 


House          Nuu 

mbei 

Number 

Number 

Cost   of j  Cost   oi 

Cost  of 

Cost   of 

Total 

number           por 

c-hes 

windows 

doors 

wire       lumber 

hardware 

labor 

cost 

1 

1 

11 

2 

$   15.26 

$     6.00 

$  2.54 

$     8.40 

$  32.20 

2 

1 

12 

2 

17.22 

6.50 

2.64 

8.40 

34.76 

3 

1 

9 

2 

15.  40 

5.75 

2.29 

8.40 

31.84 

4 

2 

7 

2 

16.34 

5.80 

2.14 

11.20 

35.  48 

5 

1 

13 

2 

15.89 

4.50 

2.64 

11.20      34.23 

6 

5 

3 

4.83 

3.00 

2.46 

5.60 

15.89 

7 

4 

3 

4.34 

2.70 

2.26 

5.60 

14.90 

8 

. 

4 

3 

4.34 

2.70 

2.26 

5.60 

14.90 

9 

5 

3 

4.83 

3.00 

2.46 

5.60 

15.89 

10 

1 

4 

3 

11.13 

3.95 

2.21 

7.00 

24.29 

11 

1 

7 

3 

10.57 

4.10 

2.31 

7.00 

23.98 

12 

1 

6 

2 

9.62 

3.85 

1.99 

7.00 

22.46 

13 

1 

6 

2 

9.62 

3.85 

1.99 

7.00 

22.46 

14 

1 

6 

2 

9.62 

3.85 

1.99 

7.00 

22.46 

15 

2 

12 

2 

22.22 

6.90 

2.69 

14.00 

45.81 

16 

1 

12 

2 

16.34 

6.00 

2.44 

8.40 

33.18 

17 

2 

3 

2 

21.17 

5.85 

1.59 

11.20 

39.81 

18 

1 

4 

3 

15.40 

4.35 

2.46 

7.00 

29.21 

19 

1 

4 

3 

15.40 

4.35 

2.46 

7.00 

29.21 

20 

1 

4 

3 

15.40 

4.35 

2.46 

7.00 

29.21 

21 

1 

10 

3 

17.64 

6.80 

3.01 

11.20 

38.65 

22 

3 

3 

3.85 

1.95 

2.21 

2.80 

10.81 

23 

1 

3 

0.60 

0.75 

1.81 

2.80 

5.96 

24 

7 

1 

4.41 

2.75 

2.27 

4.20 

13.63 

25 

3 

1 

2.97 

1.40 

1.27 

2.80        8.44 

26 

5 

3 

3.95 

1.30 

1.91 

2.80        9.96 

27 

5 

3 

3.95 

1.30 

1.71 

2.80 

9.76 

28 

5 

3 

3.95 

1.30 

1.71 

2.80 

9.76 

29 

2 

1 

1.57 

0.45 

0.67 

1.40 

4.09 

30 

2 

1 

1.57 

0.45 

0.67 

1.40 

4.09 

31 

5 

2 

4.93 

2.20 

1.59 

5.60 

14.32 

Totals 2 

0 

186 

73 

$ 304. 33 

$112.00 

$65.  11 

$200.00  $681.64 

Detailed  costs  of  the  screening  at  Lake  Village,  Ark.,  already 
referred  to,  with  galvanized  iron  wire,  costing  $3.00  per  100 
square  feet,  are  furnished  by  Derivaux,  Taylor  and  Haas,  in  a 

1  Transactions  of  First  Annual  Conference  of  Sanitary  Engineers,  U.  S. 
Public  Health  Service. 


SCREENING 


207 


report,1  from  which  the  following  table  has  been  compiled,  labor 
costing  from  40  to  50  cents  an  hour;  in  this  case,  the  chimneys 
also  were  screened. 


House 

Number    Number 

Number 

Cost  of 

Cost  of 

Cost  of 

Cost  of 

Total 

number 

chimneys   windows 

doors 

wire 

lumber 

hardware 

labor 

cost 

1 

7 

3 

$  4.52 

$  2.  15 

$  0.90 

S   11.00 

$  18.57 

2 

7 

2 

3.44 

2.15 

0.60 

6.00 

12.  19 

3 

5 

2 

2.90 

2.15 

0.60 

8.50 

14.  15 

4 

5 

2 

2.90 

2.15 

0.60 

8.50 

14.15 

5 

2 

2 

1.55 

2.15 

0.60 

8.50 

12.80 

6 

2 

3 

2.63 

2.15 

1.85 

7.90 

14.53 

7 

1 

2 

1.28 

2.65 

2.10 

12.00 

18.03 

8 

2 

2 

1.55 

2.65 

1.20 

14.00 

19.40 

9 

2 

2 

2.46 

2.40 

0.60 

7.85 

13.31 

10 

1 

3 

1.10 

2.  4.'. 

0.85 

7.00 

11.40 

11 

1 

5 

3 

3.17 

2.90 

0.85 

9.00 

15.92 

12 

1 

3 

2 

1.91 

2.  15 

0.70 

4.00 

8.76 

13 

3 

2 

1.91 

2.15 

0.70 

4.00 

8.76 

14 

1 

3 

2 

1.91 

2.15 

0.70 

4.00 

8.76 

15 

2 

2 

1.66 

4.90 

0.60 

6.90 

14.06 

16 

2 

4 

2.66 

4.90 

1.10 

10.40 

19.06 

17 

2 

4 

2.66 

4.90 

1.10 

8.80 

17.46 

18 

4 

4 

3.86 

4.90 

1.  10 

9.60 

19.46 

19 

\ 

2 

3 

2.36 

1.95 

0.85 

6.40 

1 1 .  56 

20 

3 

2 

2.09 

1.20 

0.60 

4.80 

8.69 

21 

3 

3 

2.36 

2.40 

0.85 

5.20 

10.81 

22 

3 

2 

1.82 

0.40 

0.60 

4.00 

7.82 

23 

4 

4 

3.44 

2.40 

1.10 

7.60 

14.54 

24 

4 

4 

3.98 

2.79 

1.  10 

10.00 

17.87 

25 

2 

2 

1.82 

2.44 

0.60 

7.00 

1 1 .  86 

26 

2 

•      2 

1.82 

3.  11 

1.10 

8.50 

14.53 

27 

4 

4 

3.99 

3.90 

1.60 

12.00 

21.48 

28 

4 

5 

3.98 

3.40 

1.35 

12.50 

21.23 

29 

2 

2 

1.05 

2.40 

0.60 

6.50 

10.55 

30 

4 

4 

1.43 

2.90 

1.10 

12.50 

17.93 

31 

2 

2 

1.41 

1.90 

0.70 

8.00 

12.01 

32 

4 

4 

3.  16 

2.80 

1.10 

8.00 

15.06 

33 

7 

3 

3.  16 

1.90 

0.85 

6.80 

12.71 

Totals 

32 

108 

92 

$81.93 

;  $88.89 

$31.85 

$207.75 

$469.42 

DOES  SCREENING  PAY? 

It  has  been  shown  that  good  screening  will  greatly  reduce  the 
incidence  of  the  mosquito-borne  diseases.  Costs  of  good  screen- 
ing have  also  been  discussed.  The  question  as  to  whether  or  not 
screening  will  pay,  on  a  dollar-and-cent  basis  alone,  may  now  be 
taken  up. 

1  "Malaria  Control:  A  Report  of  Demonstration  Studies,"  U.  S.  Public 
Health    Service,     1917. 


208 


MOSQUITO  ERADICATION 


As  a  result  of  the  screening  demonstration  carried  on  by  the 
U.  S.  Public  Health  Service  and  the  International  Health  Board 
near  Lake  Village,  Ark.,  already  referred  to,  it  was  found  that  the 
incidence  of  malaria,  as  revealed  by  blood  examination,  was 
reduced  from  11.97  to  3.52  per  cent  for  the  screened  group,  but 
remained  virtually  unchanged  for  the  unscreened  group.  Study 
of  the  cost  of  screening  for  the  screened  group  and  of  the  losses 
arising  from  malaria  for  both  groups  gives  the  interesting  results 
shown  in  the  following  table: 


Screened 
group 

Unscreened 
group 

Per  capita  loss  from  malaria 

$0.06 
1.76 

$2.52 

Per  capita  cost  of  screening 

Totals 

$1.82 

$2.52 

It  is  apparent  from  this  that  screening  much  more  than  paid 
for  itself,  and  this  on  the  assumption  that  it  would  last  only  2 
years.1  In  addition,  there  is  to  be  considered  the  freedom 
enjoyed  by  the  screened  group  from  annoyance  by  mosquitoes 
and  also  from  the  fly  pest  and  its  accompanying  dangers  of 
typhoid. 

1  "Malaria  Control:  A  Report  of  Demonstration  Studies,"  U.  S.  Public 
Health  Service,  1917. 


CHAPTER  XI 

OTHER    MEASURES    AND    EXPEDIENTS    AND    POINTS 
REQUIRING  INVESTIGATION 

SCOPE  OF  THIS  CHAPTER 

In  previous  chapters,  the  standard  methods  of  mosquito 
eradication  and  control  have  been  discussed  at  some  length. 
In  the  present  chapter,  it  is  intended  to  outline  various  auxiliary 
measures  in  dealing  with  mosquitoes — some  of  demonstrated 
value;  others  still  under  investigation — and  to  call  attention  to 
points  that  require  further  study  and  that  may  lead  to  results  of 
importance. 

It  may  be  stated  here  definitely  that  we  do  not  yet  know,  by 
any  means,  all  that  is  worth  knowing  about  mosquitoes.  There 
are  still  many  important  questions  that  need  clearing  up,  and  it  is 
possible  that,  as  they  are  cleared  up,  new  and  valuable  methods 
of  procedure  in  eradicating  mosquitoes  will  be  developed.  Also, 
as  our  knowledge  of  the  mosquito  increases,  it  is  not  improbable 
that  it  may  be  possible  to  effect  considerable  economies  in 
connection  with  present  methods  of  control. 

Despite  the  present  limitations  of  our  knowledge,  progress  is 
steadily  being  made.  The  problem  of  the  mosquito  is  being 
studied  from  many  different  angles,  and  a  large  number  of 
auxiliary  methods  of  dealing  with  it  have  been  proposed.  In  the 
following  sections,  a  few  of  these  will  be  discussed. 

AUXILIARY  METHODS  AND  EXPEDIENTS  IN  GENERAL 

It  will  be  noted  that  the  standard  offensive  methods  already 
described,  such  as  drainage,  oiling  and  fish  control,  are  directed 
chiefly  against  the  mosquito  in  its  early  stages;  they  are  designed 
either  to  prevent  it  from  ever  coming  into  existence,  as  drainage, 
or  to  destroy  it  before  it  matures,  as  oiling  and  fish  control. 
While  screening  is  directed  against  the  adult,  it  is  purely  pro- 
tective, and  has  no  offensive  aspects. 

While  these  measures  are  undoubtedly  based  on  correct 
principles,  nevertheless,  there  is  no  reason,  theoretically,  why 

209 

14 


210  MOSQUITO  ERADICATION 

offensive  measures  against  the  adult  should  not  be  developed  as  a 
supplementary  procedure.  In  the  plague  campaigns  against 
rats  and  ground-squirrels,  direct  offensive  measures  are  used 
against  adults  with  great  success.  The  same  may  be  said,  to 
some  extent,  in  regard  to  flies. 

Again,  it  may  be  said  that  there  is  plenty  of  scope  for  further 
protective  measures  against  adults.  There  are  millions  of  homes 
that  are  not  screened,  and  many  of  these  cannot  be  screened 
effectively.  Furthermore,  as  already  pointed  out,  screening  is 
protective  only  in  the  place  that  is  screened.  For  these  reasons, 
other  protective  measures  should  be  utilized  wherever  and  when- 
ever it  appears  that  they  will  be  of  any  value. 

DIRECT  EXTERMINATIVE  MEASURES 

The  following  measures  for  attacking  the  adult  mosquito 
appear  to  have  more  or  less  value  or  to  offer  possibilities  of 
further  development : 

1.  Direct  exterminative  measures,  preferably  by  some  biologi- 
cal enemy. 

2.  Indirect  methods  of  harassing  and  annoying,  such  as 
destroying  or  rendering  unattractive  its  harboring  and  resting 
places. 

The  most  practical  application  of  direct  exterminative  meas- 
sures  against  the  adult  mosquito  would  seem  to  be  use  of  some 
biological  enemy.  The  use  of  fish  against  the  earlier  stages  of 
the  mosquito  is  an  example  of  the  value  of  this  procedure.  There 
remains  only  to  find  some  animal  that  is  adapted  for  destruction 
of  the  adult  mosquito. 

THE  BAT  AS  A  DESTROYER  OF  ADULT  MOSQUITOES 

Doctor  Campbell  of  San  Antonio,  Tex.,  for  many  years  has 
expounded  the  view  that  the  domestic  bat,  Chiroptera,  can  be 
utilized  as  a  means  of  exterminating  adult  mosquitoes,  and,  as 
a  result  of  his  advocacy,  San  Antonio  and  other  cities  have 
installed  bat-roosts  for  this  specific  purpose.  The  idea  is  to 
encourage  development  of  enough  bats  in  each  community  greatly 
to  reduce,  if  not  eliminate,  the  mosquito  pest. 

While  Doctor  Campbell  fortifies  his  arguments  with  a  mass  of 
resolutions  and  letters  of  approval,  which  apparently  sustain 
his  conclusions,  there  seems  to  be  a  certain  amount  of  doubt 


OTHER  MEASURES  AND  EXPEDIENTS  211 

in  scientific  circles  as  to  the  general  applicability  of  the  scheme. 
Hoffman1  sums  up  the  matter  as  follows: 

"It  is  conceivable  that  bat-roosts  may  be  of  advantage  in  one  loca- 
tion, while  entirely  useless  in  another.  It  is  possible  that  bats  may 
exterminate  a  sufficient  number  of  Anopheles  to  reduce  the  mosquito 
nuisance  to  a  minimum.  Conversely,  the  enormous  number  of  bats 
required  for  effective  work  may  constitute  an  evil  in  itself  not  to  be 
tolerated  in  civilized  communities.  The  subject  has  reached  the 
stage  where,  in  my  judgment,  it  is  obviously  the  duty  of  the  several 
Government  departments  concerned  to  institute  a  thorough  investiga- 
tion and  to  make  a  full  report." 

Chidester2  gives  the  following  list  of  animals,  other  than 
fishes,  which  are  recognized  as  foes  of  the  mosquito  in  its  various 
stages : 

OTHER  ANIMAL  FOES  OF  THE  MOSQUITO 

PROTOZOA — Spirochaeta  culicis,  Diplocystis,  Nosema  stego- 
myiae,  Crithidia  fasciculata,  Herpetomonous  algeriense,  Try- 
panosoma culicis. 

COELENTERAT A— Hydra  fusca,  H.  viridis. 

PLATYHELMINTHS — Agamodislomum  martiranoi. 

NEMATHELMINTHS — Agamomermis  culicis. 

ARTHROPODA — Hydrophilus  obtusatus,  Dytiscus  marginalis, 
Acilius  sulcatus,  Nepa,  Nolonocta,  Ranatra  fusca,  Aeschna, 
Erythemis  simplicicollis,  Psorophora  ciliala,  Megarhinus  septen- 
trionalis,  Lutzia  bigotii,  Lesticocampa,  Corethra,  Tanypus  dyari, 
Lispa  sinensis,  Horpopeza  obliterate,  Tahydromia  macula,  Cordi- 
lura  haemorhoidalis,  Monedula  signata,  Emesa  longipes,  Salticus, 
Crangon  vulgaris. 

AMPHIBIA — Rana  pipiens,  R.  palustris,  Discoglossus  pictus, 
Triton  cristatus,  T.  alpestris,  Diemyctylus  tortosus,  Ambly stoma 
opacum. 

REPTILIA — Ptychozoon  homalecephalum. 

AVES — Chordeiles  virginianus,  Choetura  pelagica,  Petrochelidon 
lumfrous,  Iridoprocne  bicolor,  Hirundo  erythrogasta,  Progne 
subis,  Riparis  riparia,  Tachycineta  thalassina  lepida,  Myiochanes 
virens,  Sayornis  phoebe,  Tyrannus  tyr annus,  Anas  platyrhynches, 
Aegilitis  semipalmata,  Pisobia  pusillus. 

1  Southern  Medical  Journal,  April,  1921,  page  304. 

2  "A  Biological  Study  of  the  More  Important  of  the  Fish  Enemies  of 
the  Salt  Marsh  Mosquitoes,"  New  Jersey  Agricultural  Experiment  Stations, 
1916. 


212  MOSQUITO  ERADICATION 

MAMMALIA — Eptesicus  fuscus. 

Many  of  these,  of  course,  may  turn  out  to  be  of  no  practical 
value;  others  may  be  of  value  in  destroying  the  earlier  stages  of 
the  mosquito,  like  fish:  others  finally,  may  be  developed  into 
instruments    of    destruction    as    against    the    adult    mosquito. 

DESTRUCTION  OF  MOSQUITOES  IN  DWELLINGS 

"Swat  the  fly"  has  long  been  a  slogan  in  anti-fly  campaigns, 
in  which  this  procedure  has  been  recognized  as  a  valuable 
adjunct  to  other  methods  of  eradication.  In  anti-mosquito 
work  "swatting"  the  mosquito  is  an  equally  valuable  auxiliary 
measure. 

The  importance  of  "swatting"  the  mosquito  was  first  recog- 
nized in  the  sanitary  work  of  the  Panama  Canal  Zone,  where 
it  was  found  that  daily,  systematic  killing  or  catching  of  mosqui- 
toes in  the  laborers'  barracks  resulted  in  a  noticeable  reduction 
in  the  incidence  of  malaria.  The  application  of  this  measure 
there,  as  an  adjunct  to  screening,  was  made  possible  by  a  standard 
type  of  screened  dwelling,  a  population  under  one  central  control 
and  a  trained  organization  to  carry  out  the  work.  The  procedure 
under  these  conditions  proved  effective,  and  the  possibility  of 
its  application  to  other  conditions  should  be  more  fully 
investigated. 

Repeated  surveys  show  that  the  favorite  hiding-places  of 
mosquitoes  in  and  about  homes  include  "garrets,  bed-rooms, 
on  walls,  under  mosquito-bars,  behind  pictures,  on  clothing, 
behind  doors  and  furniture,  in  barns,  open  fire-places,  privies, 
chicken  coops,  wood  and  coal  sheds,  stables,  garages,  under 
porches  and  buildings,  in  wind-protected  corners  of  porches, 
in  empty  barrels,  trash-heaps,  wagons,  carriages,  automobiles 
and  on  spider  webs."1 

For  killing  mosquitoes  on  walls,  etc.,  probably  the  best  device 
is  an  ordinary  fly-swatter.  For  attacking  them  on  ceilings 
the  writer  has  successfully  used  a  piece  of  board  about  a  foot 
square,  covered  with  several  thicknesses  of  gauze  and  attached 
horizontally  to  the  top  of  a  pole  6  or  8  feet  long. 

Where  it  is  not  practicable  to  reach  the  mosquitoes  with  either 
of  these  weapons,  they  may  be  driven  out  by  burning  pyrethrum 
powder.     This  powder  is  not  highly  efficient  in  killing  mosquitoes, 

1  R.  H.  von  Ezdorf  in  "Anopheline  Surveys"  U.  S.  Public  Health  Service, 
1918. 


OTHER  MEASURES  AND  EXPEDIENTS  213 

unless  burned  in  comparatively  large  quantities  in  a  tightly 
closed  room  for  a  considerable  period.  A  small  amount  of  the 
powder,  however,  will  drive  them  from  their  hiding-places  to 
points  where  they  can  be  reached. 

LePrince1  sums  up  the  possibilities  of  systematic  destruction 
of  mosquitoes  in  dwellings  as  follows: 

"I  think  some  very  valuable  experimental  work  can  be  done  in  this 
country  by  applying  this  matter  of  destruction  of  Anopheles  to  houses, 
where  the  house  tenant  is  not  in  any  way  interested,  by  using  the 
children  to  do  the  catching   ... 

HARASSING  THE  MOSQUITO 

The  theory  underlying  this  measure  is  that  mosquitoes  will  be, 
to  some  extent,  dispersed  and  driven  away  if  the  environment  is 
made  unfavorable  to  them. 

It  has  been  observed  that,  generally  speaking,  the  mosquito, 
when  not  seeking  food,  spends  its  time  in  some  shaded  and, 
preferentially,  damp  place.  It  avoids  the  direct  sunlight  and, 
when  possible,  selects  a  place  where  there  is  a  certain  amount  of 
moisture.  This  being  so,  it  is  obvious  that  if  we  can  eliminate 
these  places  or  render  them  inaccessible  or  objectionable  to  it,  the 
mosquito  will  either  have  to  get  out  and  seek  some  new  harboring 
place  or,  at  its  peril,  remain  in  an  environment  that  has  become 
unfavorable  to  it. 

The  favorite  harboring  places  of  the  mosquito  about  the  aver- 
age home  appear  to  be  bushes,  clumps  of  weeds,  high  grass,  etc., 
underneath  the  house,  in  the  cellar,  in  the  garage,  under  culverts, 
in  stables  and  other  dark  places.  In  each  of  these,  a  certain 
amount  of  moisture  is  usually  found,  due  to  failure  of  the  sun  to 
penetrate  for  any  extended  period. 

In  carrying  out  this  measure,  then,  weeds  and  high  grass  within 
a  radius  of  several  hundred  feet  of  the  dwelling,  should  be  cut  and 
burned;  the  ground  under  the  house,  the  cellar,  nearby  culverts, 
stables  and  similar  harboring  places  should  be  oiled  thoroughly 
from  time  to  time;  thick  heavy  foliage  should  be  trimmed  out 
and,  if  necessary,  also  oiled  or  otherwise  treated;  the  lawn  or 
garden  hose  should  be  used  sparingly,  so  as  not  to  cause  too  much 
dampness  about  the  house. 

The  writer  has  tried  out  this  measure  for  several  seasons;  and 
it  is  surprising  what  a  difference  its  practice  will  make— it  being 
1  Southern  Medical  Journal,  April,  1921,  page  294. 


214  MOSQUITO  ERADICATION 

understood  that  it  is  of  value  only  in  ridding  the  area  of  a  brood 
of  mosquitoes  that  has  settled  there  and  is  useless  if  new  broods 
are  continually  emerging  from  nearby  breeding-places.  It 
must,  therefore,  be  used  in  connection  with  the  other  standard 
methods  already  described. 

FURTHER  PROTECTIVE  MEASURES 

When  the  offensive  measures  against  the  mosquito  fail  to  bring 
the  desired  result,  defensive  or  protective  measures  may  be 
brought  into  play.  In  addition  to  screening,  there  are,  as  already 
intimated  in  a  previous  section  of  this  chapter,  several  other 
more  or  less  valuable  protective  measures  that  may  be  used 
to  repel  the  mosquito  or  to  avert  some  of  the  consequences  of  its 
attack. 

One  of  the  most  interesting  and  suggestive  of  these  is  the  use  of 
animals  as  a  living  shield  between  mosquito  production  areas  and 
human  dwelling-places.  This  measure  arose  from  the  observation 
that  mosquitoes  frequently  are  more  numerous  in  stables,  etc., 
than  in  adjoining  dwellings. 

Rizzi1  records  several  interesting  observations  on  the  subject, 
made  in  the  vicinity  of  Trinitapoli,  Italy,  a  well-known  center  of 
malaria,  which  may  be  summarized  as  follows: 

USE  OF  ANIMALS  AS  A  PROTECTION  AGAINST  MOSQUITOES 

1.  In  a  locality  usually  non-malarious,  a  stable  was  found  to 
abound  with  Anopheles  mosquitoes.  Careful  search  led  to 
discovery  of  the  breeding-place,  a  small  basin  of  water  still 
containing  larvae.  Rizzi  holds  that  the  mosquitoes  did  not 
invade  surrounding  areas,  owing  to  the  fact  that  the  single  beast 
in  the  stable  supplied  them  with  sufficient  blood. 

2.  In  a  village  frequently  attacked  by  malaria,  only  a  few 
mosquitoes  were  found;  they  were  abundant,  however,  in  two 
large  stables,  each  about  1,500  feet  from  the  outlying  parts  of 
town.  No  larvae  were  found  in  neighboring  ponds,  although 
some  had  been  found  in  the  spring.  Rizzi  believes  that  in  this 
case,  the  mosquitoes  were  attracted  to  the  stables,  which,  in  this 
way,  protected  the  village  from  invasion. 

1  Nuovo  Indirizzo  di  Profilassi  Anti-malarica,  Ann.  d'Igiene,  Nov.  30, 
1919.  Compiled  from  "Public  Health  Engineering  Abstracts,"  U.  S. 
Public  Health  Service,  July,  2,  1921. 


OTHER  MEASURES  AND  EXPEDIENTS  215 

3.  At  Trinitapoli  itself,  Rizzi  records,  several  broods  of  mos- 
quitoes, hatched  from  larvae  in  nearby  ponds,  suddenly  emerged. 
St  ables  in  the  vicinity  of  the  ponds  were  first  invaded,  then  stables 
nearer  town  and,  finally,  some  outlying  houses.  Anti-mosquito 
measures  were  then  pressed,  and  the  invasion  was  arrested,  vir- 
tually no  mosquitoes  entering  the  town  itself.  The  conclusion 
seems  to  be  that  the  stables  attracted  the  mosquitoes  and 
detained  them  long  enough  to  enable  the  anti-mosquito  measures 
to  be  applied. 

Rizzi,  however,  emphasizes  the  fact  that  reliance  on  the  attrac- 
tions of  stables,  etc.,  is  not  sufficient  in  itself.  He  appears  to 
believe  that  the  use  of  animals  in  this  way  is  merely  one  factor  that 
may  be  of  advantage  in  connection  with  the  usual  anti-mosquito 
measures,  and  this  view  appears  reasonable  to  the  writer.  Where 
stables  can  be  located  between  the  dwelling  and  a  marsh,  pond  or 
similar  breeding-place,  it  is  believed  advantageous  so  to  locate 
them.  Use  of  land  between  the  dwelling  and  the  breeding-place 
for  a  pasture  might  also  be  advantageous. 

APPLICATION  OF  SUBSTANCES  REPELLENT  TO  MOSQUITOES 

This  measure  cannot  be  relied  upon  to  any  great  extent,  as 
most  of  the  substances  in  use  at  present  evaporate  within  a  few 
hours,  and  the  mosquitoes  return. 

These  substances  are  generally  used  at  night.  They  are  either 
rubbed  on  the  face  and  hands  or  dropped  on  the  pillow  or  on  a 
towel  which  is  hung  over  the  head  of  the  bed. 

Oil  of  citronella  probably  is  the  most  efficacious  of  the  mos- 
quito-repelling substances  now  in  use.  Others  employed  include 
spirits  of  camphor,  oil  of  peppermint,  oil  of  pennyroyal,  lemon- 
juice,  vinegar  and  kerosene.  Several  patented  preparations  are 
also  on  the  market.  None  of  these  seem  to  last  until  morning, 
however. 

The  writer  has  found  bi-weekly  or  tri-weekly  oiling  of  the  floor 
with  kerosene  is  about  as  effective  as  anything  else  along  this  line. 
The  odor,  of  course,  is  more  or  less  disagreeable  to  the  person 
occupying  the  room,  but  it  is  equally  as  disagreeable  to  the 
mosquitoes,  and,  as  a  result,  they  usually  keep  out. 

Another  procedure  that  may  conveniently  be  mentioned  here  is 
that  of  making  a  smudge.  This  measure  is  tolerably  effective, 
as  the  mosquitoes  generally  flee  from  the  smoke,  but  it  is  almost 
as  objectionable  to  the  occupants  of  the  room  as  the  mosquitoes 


216  MOSQUITO  ERADICATION 

are.     This  is  a  common  practice  in  negro  cabins  in  the  malarious 
districts  of  the  South. 

USE  OF  QUININE  FOR  MALARIA 

Use  of  quinine  is  of  value  only  in  cases  of  malaria;  its  effect 
is  to  destroy  the  malaria  plasmodia,  which  have  been  injected 
into  the  blood  of  the  malaria  patient  by  infected  Anopheline 
mosquitoes.  Quinine,  therefore,  is  of  no  avail,  until  the  person 
has  been  bitten  by  the  mosquito.  It  is  the  last  measure  of 
defense.  Quinine  is  of  no  value,  however,  in  the  treatment  of 
yellow  fever,  dengue  or  filariasis. 

The  standard  treatment  for  malaria  recommended  by  the 
National  Malaria  Committee  in  the  hope  that  it  would  be  gen- 
erally adopted  by  practicing  physicians  wherever  malaria  pre- 
vails, is  as  follows : 

"For  the  acute  attack,  10  grains  of  quinine  sulphate  by  mouth  three 
times  a  day  for  a  period  of  at  least  3  or  4  days,  to  be  followed  by  10  grains 
every  night  before  retiring  for  a  period  of  8  weeks.  For  infected  persons, 
not  having  acute  symptoms  at  the  time,  only  the  8  weeks'  treatment  is 
required. 

"The  proportionate  doses  for  children  are:  Under  1  year,  lA  grain; 
1  year,  1  grain;  2  years,  2  grains;  3  and  4  years,  4  grains;  5,  6  and  7 
years,  5  grains;  8,  9  and  10  years,  6  grains;  11,  12,  13  and  14  years,  8 
grains;  15  years  or  older,  10  grains." 

The  object  of  the  treatment  is  not  only  to  relieve  the  clinical 
symptoms,  but  also  to  disinfect  the  patient  in  order  to  prevent 
relapses  and  transmission  of  the  disease  to  others. 

DEMONSTRATIONS   OF  THE  VALUE   OF   MASS  TREATMENT    BY 

QUININE 

Where  malaria  assumes  an  epidemic  character  and  very  large 
percentages  of  the  population  are  infected,  mass  treatment  by 
quinine  has  given  excellent  results.  Prominent  among  the 
successful  demonstrations  of  this  kind  may  be  mentioned  the  work 
in  the  Panama  Canal  Zone,  the  work  of  the  Germans  in  Africa 
and  the  work  of  the  Japanese  in  Formosa. 

In  1920,  a  very  successful  demonstration  of  this  kind  was 
carried  out  in  Georgia.  In  the  area  in  question,  there  were 
about  2,900  acres  in  cultivation  and,  according  to  Abercrombie,1 
the  annual  loss  in  this  area  due  to  malaria  alone  was  something 

1  Southern  Medical  Journal,  April,  1921,  page  286. 


OTHER  MEASURES  AND  EXPEDIENTS  217 

over  $13  an  acre.  In  tabulating  the  history  cards  of  persons 
receiving  the  treatment,  it  was  found  that  71  per  cent  reported 
having  had  malaria  within  the  preceding  5  years;  21  per  cent 
reported  having  had  malaria  in  1919;  and  13.5  per  cent  reported 
having  had  malaria  some  time  in  1920  before  applying  for 
treatment. 

Discussing  the  demonstration,  Abercrombie1  says: 

"There  were  600,000  doses  of  quinine  given  .  .  .  The  people  who 
took  the  treatment  were  10,339,  divided  as  follows:  white  people, 
6,849,  and  colored,  3,490.  There  were  1,691  families.  I  think  the 
report  shows  that  out  of  this  total  .  .  .  there  were  something  like 
27  people  who  developed  chills  after  completing  the  treatment.  We 
figured  that  this  cost  approximately  50  cents  per  capita  over  the  county. 
It  cost  probably  $1.50  for  each  person  taking  the  treatment,  but,  since 
it  is  a  county-wide  proposition,  we  are  figuring  it  on  a  per  capita  basis 
in  the  county." 

The  campaign  was  started  by  interesting  the  plantation  owners 
and  managers  from  an  economic  standpoint.  Their  assistance 
was  obtained  in  distributing  the  quinine  to  their  tenants  and 
employes;  in  addition,  14  free  dispensaries  were  established  at 
various  points  in  the  county.  In  all,  about  two-fifths  of  the 
population  of  the  county  was  treated. 

QUININE  VERSUS  ANTI-MOSQUITO  MEASURES 

While  quinine,  as  has  been  shown,  is  very  valuable  in  coping 
with  malaria  epidemics,  use  of  quinine  should  in  no  sense  be 
considered  as  a  satisfactory  substitute  for  anti-mosquito  measures. 

In  the  first  place,  quinine  is  merely  a  remedy  for  but  one  of  the 
effects  of  mosquito  bites.  It  has  no  bearing  on  the  annoyance 
caused  by  mosquitoes  of  all  species  and  the  grave  effects  of  this 
annoyance  upon  the  health.  Moreover,  quinine  is  of  no  value  in 
coping  with  those  other  consequences  of  mosquito  bites  which 
take  the  form  of  yellow  fever,  dengue  and  filariasis. 

It  also  seems  probable  that  over  a  period  of  years,  covering 
entire  populations,  administration  of  quinine  would  frequently 
prove  more  costly  than  execution  of  anti-mosquito  measures. 

There  is  no  doubt  that  quinine  has  its  place  in  the  mosquito 
problem,  but  that  place  is  necessarily  a  limited  one. 

1  Southern  Medical  Journal,  April,  1921,  page  286. 


218  MOSQUITO  ERADICATION 

POINTS  THAT  REQUIRE  FURTHER  INVESTIGATION1 

As  stated  in  an  earlier  part  of  this  chapter,  there  are  still 
many  points  in  connection  with  mosquitoes  that  require  further 
investigation.  These  investigations  may  result  in  improvements 
in  our  present  methods  of  dealing  with  mosquitoes  or  in  the 
development  of  entirely  new  measures  of  control. 

Among  the  points  that  may  be  profitably  studied,  the  following 
may  be  mentioned: 

1.  Hibernation  of  adult  mosquitoes  of  the  various  species. 
What  are  the  natural  hibernation  places?  What  relation  have 
shade,  shelter,  direction  of  prevailing  winds,  proximity  of  stand- 
ing water,  etc.,  to  the  hiberation  places?  Can  any  method  be 
devised  whereby  the  mosquito  may  be  successfully  attacked 
during  the  hibernation  period? 

2.  Survival  of  larvae  over  the  winter.  Can  any  method  of 
attack  be  devised  that  will  be  of  value? 

3.  Life  of  the  egg.  What  conditions  of  dryness  will  eggs  of 
the  various  species  and  genera  withstand?  How  long  will  eggs 
of  the  various  species  and  genera  retain  their  vitality?  What 
circumstances  result  in  depriving  the  eggs  of  vitality? 

4.  Flight  distances  of  the  various  species  and  genera,  and  local 
conditions  influencing  flight,  such  as  moisture,  wind,  etc. 

5.  Aquatic  plants  influencing  mosquito  production.  What  are 
they,  in  what  manner  do  they  influence  production  and  how  can 
they  be  utilized  in  mosquito  control  work? 

6.  Factory  and  chemical  wastes  which  prevent  •  or  favor 
mosquito-breeding.  What  are  they,  and  can  they  be  utilized  in 
mosquito  control  work? 

7.  How  is  it  that  some  places,  which  apparently  should,  do  not 
produce  mosquitoes?  What  is  the  connection  between  the 
animal  and  plant  life,  chemical  and  physical  properties  of  the 
water  in  such  pools  and  the  absence  of  breeding  therein? 

8.  Some  larvicide  that  does  not  require  replacement  as  soon  as 
oil  and  the  larvicides  now  in  use.  Some  larvicide  that  will  be 
cheaper  than  those  now  in  use. 

These  are  some  of  the  maii3r  points  about  mosquitoes  that 
more  light  is  desired  on.  Observation  of  field  workers  may  result 
in  considerable  progress  being  made. 

1  Adapted  from  circular  of  Office  of  Field  Investigations  of  Malaria,  U.  S. 
Public  Health  Service. 


CHAPTER  XII 

RURAL  MOSQUITO  AND  MALARIA  CONTROL 

UNFAVORABLE  FACTORS  IN  RURAL  CONTROL 

Mosquitoes  and  mosquito-borne  diseases  are,  in  general,  more 
troublesome  in  the  rural  regions  than  in  the  cities.  Construc- 
tion of  water-supply  and  sewerage  .  systems  eliminates  a  mul- 
tiplicity of  artificial  breeding-places,  while  city  grading  and 
ditching  help  to  provide  a  means  for  rain-fall  to  run  off,  thus 
largely  obviating  the  rain-water  pool  as  a  breeding-place. 

In  the  rural  areas,  there  are  always  a  number  of  natural  breed- 
ing-places. To  these  must  be  added  the  man-made  breeding- 
places,  more  or  less  necessary  in  the  country,  but  not  in  the  city, 
such  as  cisterns,  stock-troughs,  stock-ponds,  cesspools  and  a  host 
of  others.  Furthermore,  a  certain  amount  of  anti-mosquito  work 
now  is  being  done  in  most  large  cities  that  require  it,  while  in  the 
country,  owing  to  sparsity  of  population  and  the  large  areas 
involved,  community  anti-mosquito  measures  are  generally 
impracticable  at  present,  due  to  the  heavy  per  capita  cost.  It 
will  be  seen,  therefore,  that  at  the  present  time,  at  least,  the 
problem  of  mosquito  control  in  rural  districts  is  essentially  an 
individual  one. 

Towns  and  villages  without  modern  sanitary  conveniences  and 
the  unsewered  outlying  suburbs  of  the  cities  are  also  more  diffi- 
cult to  handle  than  the  cities,  for  the  same  reasons  given  above. 
Anti-mosquito  measures  in  them  are,  however,  somewhat  more 
practicable  than  in  the  country  itself,  because  of  the  greater 
density  of  population,  which  means  that  the  cost  will  be  spread 
over  a  much  greater  number  of  beneficiaries  per  unit  of  area. 

FAVORABLE    FACTORS    IN    RURAL    CONTROL 

On  the  other  hand,  however,  it  may  be  said  that,  as  a  rule, 
the  rural  home  is  better  situated,  from  an  anti-mosquito  stand- 
point than  many  urban  homes.  Frequently  the  rural  home  is  situ- 
ated on  fairly  high  ground,  where  the  wind  can  reach  it  and  at  a 
respectful  distance  from  such  natural  breeding-places  as  swamps, 
etc. 

219 


220 


MOSQ  UI  TO  ERA  DICA  TION 


Furthermore,  the  cleanly  and  progressive  farmer  need  not  suffer 
from  the  sloth,  ignorance  and  negligence  of  his  neighbors,  as  is 
often  the  case  with  the  city  or  town  man.  Houses  are  usually 
far  enough  apart  to  render  impossible  much  annoyance  from 
mosquito-breeding  in  and  about  the  homes  of  neighbors.  Thus, 
in  order  to  be  free  from  mosquitoes,  the  intelligent  countryman 
need  only  keep  his  own  home  in  shape. 

Sometimes,  this  is  a  comparatively  easy  matter;  sometimes  it 
is  almost  impossible.     Much  depends  upon  the  topographical 


*^"^P 

w 

Wr*- 

*--■ 

■ 

'  ■*'   :'^l 

■'                 1 '  1 

« - . ' 

*  Ifl 

Mr'^'T'' 

- 

(Photo  by  E.  B.  Johnson,  C.  E.) 
Fig.   144. — This  ditch,  in  places  15  feet  deep  and  more  than  a  mile  long,  was 
dug  by  5  Alabama  farmers  as  a  land-improvement  project.     It  drained  a  swamp 
of  nearly  50  acres. 

and  meteorological  conditions  of  the  district.  Thus,  in  the  delta 
country  of  the  Mississippi,  a  region  of  fertile,  low-lying  soil, 
interspersed  with  bayous  and  slowly-moving  streams  and 
having  a  heavy  rain-fall,  an  individual  can  do  but  little.  In  a 
well  drained  section,  however,  where  the  home  is  favorably 
situated,  there  is  no  reason  why  mosquitoes  should  cause  any 
annoyance. 

NEED   FOR  A   SURVEY 

In  undertaking  mosquito  control  measures  about  the  average 
rural  home,  probably  the  first  consideration  is  cost.     It  would  be 


RURAL  MOSQUITO  AND  MALARIA  CONTROL  221 

unreasonable  to  spend  more  money  for  mosquito  control  than 
such  control  is  worth.  The  first  thing,  therefore,  is  to  ascertain 
what  amount  is  available  for  the  work.  This  done,  it  will  be 
possible  to  determine  just  what  measures  will  give  the  most 
relief  for  the  money. 

Thus,  while  it  may  not  be  possible  to  eliminate  mosquitoes 
entirely  from  the  home,  it  may  be  possible  to  reduce  them  greatly 
at  very  slight  expense.  Again,  it  may  be  that,  while  a  certain 
measure,  such  as  tile  drainage,  for  example,  might  cost  too  much 
as  an  anti-mosquito  measure  alone,  the  other  benefits  that  come 
from  it,  as  improvement  of  the  crop  yield,  might  make  the  project 

feasible. 

The  first  essential,  then,  after  determining  the  amount  avail- 
able for  the  work  is  to  make  a  careful  survey  of  the  situation  from 
every  angle.  Doubtless,  the  survey  will  show  that  a  consider- 
able amount  of  breeding  can  be  eliminated  at  no  cost  whatsoever, 
other  than  a  little  care  and  study.     . 

CONTROL  MEASURES  ABOUT  THE  AVERAGE  HOME 

The  first  step  to  take  in  eliminating  mosquito-breeding  about 
the  rural  home  is  to  stop  giving  aid  and  assistance  to  the  enemy. 
This  means  that  no  breeding  should  be  made  possible  by  ignorance 
or  carelessness  on  the  part  of  the  farmer  and  his  family.  In 
other  words,  cisterns,  water-barrels,  wells,  etc.,  should  either  be 
made  mosquito-proof  or  else  should  be  oiled  weekly  or  stocked 
with  larva-eating  fish.  The  cess-pool  should  be  inspected  and, 
if  necessary,  made  mosquito-tight.  Old  cans  likely  to  hold 
water  should  be  hauled  away.  The  roof-gutters  should  be 
cleaned  out  and,  if  necessary,  re-hung.  Water-troughs  should 
be  cleaned  out  weekly  or  stocked  with  fish.  Every  potential 
breeding-place    about    the    home    should    be    closely    watched. 

The  next  step  should  be  screening.  This  should  be  done  pro- 
perly and  effectively,  along  the  lines  already  described.  If  the 
house  is  already  screened,  any  repairs  necessary  should  be  made 
at  once.     The  chimneys  should  not  be  forgotten. 

These  two  steps  should  suffice  to  prevent  any  considerable 
annoyance   by   mosquitoes   in   most   properly   situated   homes. 

FURTHER  MEASURES 

Sometimes,  further  measures  are  necessary.  It  may  be  that 
the  home  is  located  near  borrow-pits  or  other  depressions  that 


222 


MOSQ  UI  TO  ERA  DICA  TION 


Fig.   145. — Making    a    concrete    privy-vault    mosquito-proof.     All    cracks    are 

plastered  over. 


(Photo  by  E.  H.  Magoon,  C.  E.) 
Fig.   146. — While  this  pond  was  free  from  mosquito  larvae,   owing  to    the 
activities  of  Gambusia,  there  was  abundant  breeding  in  the  barrel  which  the  fish 
were  unable  to  enter. 


RURAL  MOSQUITO  AND  MALARIA  CONTROL  223 

hold  water  for  considerable  periods.  In  this  case,  the  holes 
should  be  filled  or  drained,  in  accordance  with  the  suggestions 
outlined  in  a  previous  chapter. 

Should  the  house  be  near  a  flowing  stream,  fish  control  probably 
would  be  the  best  method  of  attack.  Even  though  the  edges  of 
the  stream  were  not  cleaned  periodically,  a  certain  measure 
of  protection  would  always  be  assured.  Should  the  stream  be 
one  that  dries  up  from  time  to  time,  probably  the  best  thing  to  do 
would  be  to  oil  it,  whenever  necessary,  or,  if  not  too  costly, 
re-channel  the  stream,  so  that  no  water  would  stand  in  it  for 
longer  than  a  few  days. 

PROTECTING  HOMES  IN  SWAMPS,  ETC. 

A  home  situated  in  or  near  a  swamp  would  give  more  trouble. 
In  this  case,  it  probably  would  pay,  in  the  long  run,  if  funds 
were  available,  to  drain  the  swamp.  If  this  were  impracticable, 
however,  for  any  reason,  there  are  several  things  that  could  be 
done,  in  addition  to  screening  and  elimination  of  breeding  about 
the  home,  that  would  be  of  great  assistance.  Among  them  are 
the  following: 

1.  Cut  down  brush,  tall  weeds  and  grass  that  harbor  mos- 
quitoes. Make  the  yard  about  the  house  a  shrubless  one — open 
to  the  sun  and  wind  at  all  times.     High  trees  may  be  left. 

2.  Plant  a  screen  of  trees  some  distance  from  the  house  between 
the  breeding-place  and  the  house.  This,  according  to  Carter,1 
serves  to  hide  the  lights  of  the  house  from  the  marsh  or  stops  the 
mosquitoes  brought  by  the  breeze  from  their  breeding-places, 
or  both. 

3.  Stock  the  swamp  or  those  parts  of  it  adjacent  to  the  house 
with  larva-destroying  fish. 

4.  Try  starting  a  bat-roost.  While  some  authorities  are 
doubtful  of  the  efficacy  of  this  procedure,  it  would  cost  but 
little  to  try  it  out. 

5.  Oil  nearby  portions  of  the  swamp  from  time  to  time  or 
install  a  few  submerged  drips  therein. 

6.  Build  the  stables  between  the  house  and  the  swamp,  at 
some  distance  from  the  former.  If  the  stables  are  already  built 
elsewhere,  or  there  are  none,  pasture  cattle,  hogs  or  other  domes- 
tic animals  between  the  house  and  the  swamp. 

1  "Anti-malarial  Measures  for  Farm-houses  and  Plantations."  U.  S. 
Public  Health  Service,   1919. 


224  MOSQUITO  ERADICATION 

7.  Make  use  of  some  mosquito-repelling  substance  in  the  home. 

8.  Kill  all  mosquitoes  that  succeed  in  penetrating  the  screens 
or  otherwise  entering  the  house. 

9.  If  symptoms  of  malaria  develop,  use  quinine,  as  directed  in 
a  previous  chapter. 

THE  RICE-FIELD  PROBLEM 

An  area  within  or  near  a  rice-field  is  the  worst  possible  site  for 
a  home  from  an  anti-mosquito  point  of  view. 

In  the  light  of  our  present  knowledge,  there  is  no  really  effec- 
tive means  of  protection  in  such  a  case.  This  is  due  to  the 
methods  used  in  growing  rice,  which  call  for  flooding  of  the  culti- 
vated area  for  several  months.  In  the  Arkansas  rice  section, 
flooding  water  is  first  applied  when  the  rice  is  3  to  5  inches  high; 
the  depth  is  increased  with  the  growth  of  the  rice  until  a  depth 
of  4  to  6  inches  is  reached,  and  this  depth  is  maintained  during 
the  growing  season.  It  will  be  seen  therefore,  that  rice-fields 
constitute  an  ideal  breeding-place,  since  there  is  quiescent  water 
and  dense  vegetation. 

Some  slight  measure  of  success  in  reducing  larvae  by  means  of 
Gambusia  affinis  is  reported  by  Tarbett.1  He  states,  however, 
that  they  fail  generally  to  penetrate  the  rice,  remaining  chiefly 
in  the  more  open  water  along  the  levees. 

Tarbett1  also  reports  that  broad-casting  oil-soaked  saw-dust 
appeared  to  give  somewhat  encouraging  results.  Dry  red-oak 
saw-dust  was  used.  Thirty  gallons  of  oil,  soaked  up  into  10 
bushels  of  saw-dust,  sufficed  for  one  acre.  "The  results  obtained 
were  encouraging,"  he  says,  "breeding  being  controlled  for  a 
period  of  two  weeks  after  application,  and  this  without  an  appre- 
ciable effect  upon  the  rice.  In  this  experiment,  fuel  oil  appeared 
to  give  better  results  than  did  mixed  oil"  (mixed  with  kerosene). 

THE  RICE-FIELD  PROBLEM  ABROAD 

According  to  Gunasekara,2  little  rice  is  raised  in  Ceylon  because 
of  the  increased  incidence  of  malaria  which  it  gives  rise  to  and  of 
the  vigorous  methods  of  combatting  the  infection  carried  out 
there.  These  include:  abandonment  or  removal  of  all  dwelling- 
places  within  a  mile  of  the  rice-fields;  destruction  of  all  harboring 

1  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 

-  Journal,  Ceylon  Branch,  British  Medical  Association,  1919. 


RURAL  MOSQUITO  AND  MALARIA  CONTROL  225 

places  for  adults  within  the  same  radius;  compulsory  screening 
of  dwelling-places;  exclusion  of  all  outside  labor  without  previous 
blood-examination;  the  prophylactic  and  curative  administration 
of  quinine;  and  the  removal  of  all  infective  cases  from  the  area. 

Legendre  reports  that  in  Madagascar,  Cellia  squamosa  and 
C.  pharoensis,  local  Anopheline  hosts  of  malaria,  manifest  a 
preference  for  rice-fields  as  breeding-places  as  against  marshes 
and  swamps.  He  asserts  that  malaria  is  more  prevalent  in  the 
hill  rice-fields  than  in  the  lowland  fields,  and  attributes  this  fact 
to  the  greater  abundance  of  fish  in  the  lowland  rice-fields. 
Recommendations  made  to  combat  malaria  in  Madagascar 
include  institution  of  an  anti-larval  service,  forbidding  of  irriga- 
tion in  the  vicinity  of  towns  and  compulsory  culture  of  fish, 
wherever  practicable. 

According  to  Carter,2  attempts  to  control  malaria  about  the 
rice-fields  of  Italy  have  been  given  up.  He  states  that  cultiva- 
tion of  rice  is  now  forbidden  within  2  kilometers  of  a  village. 

Carter  states  that  in  1917  it  was  estimated  that  about 
$40,000,000  was  invested  in  the  production  of  rice  in  the  United 
States  and  that  this  investment  is  rapidly  increasing. 

COMMUNITY  MEASURES  IN  RURAL  AREAS 

As  has  been  already  indicated,  community  offensive  measures 
against  the  mosquito  at  the  present  time  are  rarely  carried  out  in 
rural  sections,  due  to  the  sparsity  of  population  per  unit  of  area 
and  the  heavy  consequent  per  capita  cost. 

Sometimes,  however,  considerable  valuable  anti-mosquito 
work  is  clone  by  drainage  district  organizations,  as  the  result  of 
measures  designed  primarily  as  agricultural  improvements. 
While  this  sort  of  work  is  not  so  effective,  from  an  anti-mosquito 
standpoint,  as  work  expressly  designed  to  rid  the  community  of 
mosquitoes,  it  is,  nevertheless,  of  considerable  assistance. 

Again,  two  or  more  farmers  may  combine  to  carry  out  a  tile 
drainage  scheme.  This,  likewise,  has  its  value,  from  a  health 
viewpoint. 

However,  it  would  appear  that  the  rural  population  will  have  1 1  > 
become  much  denser  and  land  will  have  to  increase  greatly  in 
value  before  it  will  be  practicable  to  carry  out  in  most  rural 

i  Bulletin,  Soc.  Path.  Exot.,  Feb.  9,  1921. 

2  Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers, 
U.  S.  Public  Health  Service,  1919. 

15 


226  MOSQUITO  ERADICATION 

communities  the  direct  offensive  anti-mosquito  campaigns  that 
are  being  waged  in  cities,  towns  and  villages  today. 

Several  community  protective  projects  have  been  successfully 
carried  out,  however.  These  include  both  screening  and  quinine- 
treatment  campaigns.  Some  of  these  have  extended  over  com- 
paratively wide  areas,  and  have  succeeded  in  greatly  reducing  the 
incidence  of  malaria. 

RURAL  COMMUNITY  PROTECTIVE  DEMONSTRATIONS 

An  interesting  demonstration  of  the  efficacy  of  screening  as  a 
community  protective  measure,  carried  out  on  a  group  of  planta- 
tions near  Lake  Village,  Ark.,  is  described  in  the  chapter  on 
screening.  In  this  demonstration,  no  other  measure  than 
screening  was  employed;  yet  a  reduction  of  70.6  per  cent  in  the 
incidence  of  malaria  was  obtained  at  an  annual  per  capita  cost  of 
only  $1.76. 

In  connection  with  this  same  demonstration,  an  investigation 
as  to  the  efficacy  of  quinine  treatment  was  carried  out  on  another 
group  of  plantations.  Of  a  total  of  306  persons  who  received 
treatment,  69  were  given  sterilizing  doses  and  the  remainder,  237, 
were  given  immunizing  doses.  A  parasite  index  taken  in  May, 
1916,  at  the  beginning  of  the  work,  and  again  in  December  of  the 
same  year,  showed  a  reduction  of  64.45  per  cent.  The  per 
capita  cost  of  the  work,  omitting  overhead  expenses,  was  57 
cents.  The  cost  of  malaria  per  capita  for  a  control  untreated 
group  was  $2.52. 

In  1918,  a  demonstration  of  malaria  reduction  by  quinine 
treatment  of  plasmodia  carriers  was  carried  out  in  Sunflower 
County,  Mississippi.  The  county  had  a  population  of  about 
9,000,  about  1,000  living  in  the  town  of  Ruleville  and  the  rest 
on  cotton  plantations.  A  survey  showed  that,  of  the  rural 
population,  40  per  cent  had  had  clinical  malaria  within  12 
months  and  that,  of  the  remaining  60  per  cent,  22  per  cent  had  the 
parasites  in  their  blood.  On  one  plantation,  having  a  tenant 
population  of  600,  the  average  annual  physicians'  bill  for  the 
preceding  10  years  had  been  approximately  $4,000,  of  which 
$3,000  was  attributed  to  malaria.  As  a  result  of  the  work,  there 
was  no  transmission  of  malaria  in  Ruleville  during  the  year,  and 
the  town  was  free  from  mosquitoes.  In  the  rural  area,  the  reduc- 
tion in  the  incidence  of  malaria  during  the  year  was  estimated  at 


RURAL  MOSQUITO  AND  MALARIA  CONTROL  227 

80  per  cent.     The  per  capita  cost  of  the  work  in  Ruleville  was  41 
cents  and  in  the  rural  area,  $1.08. 

In  Chapter  XI  is  described  another  extensive  community 
demonstration  of  quinine  treatment  in  Georgia,  which,  at  a  cost 
of  only  about  $1.50  per  person  taking  treatment,  resulted  in  the 
almost  total  elimination  of  malaria  symptoms  in  more  than 
10,000  persons 


APPENDIX  A 

TABLE    TO    DETERMINE    SPECIES    OF    CERTAIN    COMMON 
AMERICAN  MOSQUITOES 

The  following  table,  prepared  by  Weiss  and  Patterson,  is  reprinted  from 
Headlee's  valuable  pamphlet,  "The  Mosquitoes  of  New  Jersey  and  Their 
Control,"  with  some  abridgment  and  with  certain  changes  in  nomenclature 
suggested  by  the  work  of  Howard,  Dyar  and  Knab : 

ADULTS 
Series  X  in  Which  the  Wings  are  Spotted 

PALPI  UNIFORMLY  DARK  BROWN 

Wings  with  two  white  spots  on  the  front  margin;  last  vein  white  with 

black  ends,  Anopheles  punctipennis  Say. 
Wings  with  four  distinct  brown  spots;  last  vein  wholly  dark  brown, 

Anopheles  quadrimaculalus  Say. 
PALPI  WHITE  MARKED  AT  BASE  OF  JOINTS 

Last  vein  white  marked  with  three  black  spots,  Anopheles  crucians 

Wied. 

Series  Y  in  Which  the  Wings  are  not  Spotted 

A.  IN  WHICH  THE  FEET  ARE  WHITE  OR  YELLOWISH  BANDED 

I.  The   Beak   has   a   More   or  Less  Distinct  White   Band  or 
Ring  at  or  Near  its  Middle. 

(a)  The  abdomen  has  a  yellowish  stripe  down  its  middle,  and  sides 
of  thorax  are  white  below  a  black  edging,  Aedes  sollicitans 
Wlk. 

(b)  The  abdomen  has  no  yellowish  stripe.  Sides  of  thorax  are 
not  white. 

1.  A  large,  blackish  species  with  a  narrow  white  band  near 
the  tip  of  the  femur;  the  tibia,  white-spotted,  Psoro- 
phora  (Janthinosoma)  columbiae  D.  and  K. 

2.  A  large  brown  species  with  a  lighter  band  near  the  tip 
of  the  posterior  tibia,  the  latter  not  spotted,  Mansonia 
perturbans  Wlk. 

3.  A  smaller,  blackish  species,  without  markings  on  femur 
or  tibia,  Aedes  taeniorhynchus  Wied. 

II.  The  Beak  is  Without  Band  or  Ring;  Uniform  in  Color 

(a)  The  joints  of  the  feet  or  tarsi  are  banded  or  ringed  at  base 
only. 

1.  An    extremely    large,    brownish-black    species.     Legs 
fringed  with  erect  black  scales,  Psoropliora  ciliata  Fabr. 
228 


APPENDIX  229 

2.  A  very  large  species  with  very  scaly  wings,  the  sides  of 
the  thorax  and  bands  of  the  abdomen  and  feet,  white, 
Acdes  grossbecki  D.  and  K. 

3.  Wings  thickly  clothed  with  mixed  yellow  and  brown 
scales.  Thorax  with  broad,  brown  central  stripe. 
First  tarsal  segment  of  anterior  legs  not  banded,  Aedes 
fitchii  Felt. 

4.  A  small,  dark  species  with  lightly  scaled  wings;  the 
white  bands  of  the  feet  narrow;  those  of  the  abdomen 
nearly  divided  in  the  center,  Aedes  vexans  Meig. 

5.  A  good-sized  brown  species  with  the  bandings  yellowish 
rather  than  white;  these  of  the  abdominal  segments 
only  a  little  or  not  at  all  notched  at  the  middle,  Aedes 
cantator  Coq. 

6.  Very  like  the  preceding;  but  the  bands  of  the  abdomen 
and  feet  are  broader  and  somewhat  lighter.  Breeds 
only  in  fresh  water  areas,  Aides  stimvlans  Walker. 

7.  Very  like  the  two  precediug,  but  thorax  has  a  central 
brown  stripe,  Aedes  abfttchii  Felt. 

(£>)  The  joints  of  the  hind  feet  at  least  are  white-banded  or  ringed 
at  both  base  and  tip,  while  last  joint  of  the  hind  tarsi  is 
usually  entirely  white. 

1.  A  good-sized  brown  species,  the  thorax  without  lines  or 
marks;  bands  of  tarsal  joints  broad,  Aedes  canadensis 
Theob. 

2.  A  small,  blackish  species  with  top  of  thorax  covered  with 
gray  hair  and  a  dark  line  down  its  center;  bands  on 
tarsi  are  white  and  narrow,  Aedes  atropalpus  Coq. 

(c)    All  of  last  two  tarsal  joints  and  apex  of  middle  joint  white. 

1.  A  large  or  medium-sized  species,  black  with  deep  purple 

reflections,  Psorophora  (Janthinosoma)  sayi  D.  and  K. 

B.  IX  WHICH  THE  FEET  ARE  UNIFORM  IX  COLOR,  XOT  IX  AXY 
WAY  MARKED  OR  BAXDED 

I.  The  Thorax  is  Marked  in  Some  Way  With  Stripes  or  Spots, 
or  the  Sides  are  White  or  Golden  Brown. 

(a)  Species  with  longitudinal  white  or  blue  stripes. 

1.  There  are  two  white  longitudinal  stripes;  the  species 
is  moderate-sized  and  blackish,  Aedes  trivittatus  Coq. 

2.  There  is  a  well-defined  broad  central  white  band,  and 
the  top  of  the  head  is  also  white,  Acdes  atlanticus  D.  and 
K. 

3.  There  is  a  diffuse  white  central  stripe,  not  defined  as 
before;  a  very  small  blackish  species,  Aedes  dupreei  Coq. 

4.  There  is  a  central  bluish  stripe,  also  blue  spots.  A 
small,  dark-brown  species,  Uranotaenia  sapphirina  O.  S. 

(b)  Species  in  which  the  thorax  is  yellowish,  white  or  brown, 
leaving  a  blackish  central  stripe  or  two,  usually  not  sharply 
defined;  all  of  moderate  size. 


230  MOSQUITO  ERADICATION 

1.  The  thorax  is  yellowish;  brownish  abdomen  with  narrow 
white  bands,  Aedes  hirsuteron  Theob. 

2.  The  thorax  is  golden  yellow.  The  abdomen  is  almost 
black,  with  broad,  white  bands,  Aedes  abserratus  Felt. 

3.  The  thorax  is  golden  brown;  the  abdomen  not  banded; 
the  legs  are  black,  Aedes  aurifer  Coq. 

4.  The  thorax  is  silvery-white  at  the  sides,  not  extending 
much  on  the  upper  surface,  most  of  which  is  black;  the 
abdomen  is  not  banded,  Aedes  triseriatus  Say. 

(c)  Species  in  which  the  thorax  is  white-dotted  only. 

1.  There  are  two  small,  white  dots  on  each  side  of  the 
middle  and  a  U-shaped  mark  at  the  base;  the  abdomen 
is  banded,  Culex  restuans  Theob. 

(d)  Species  in  which  the  entire  under  surface  is  silvery  white  or 
yellowish. 

1.  A  small  form,  having  dorsal  surface  black;  stripes  on  the 
thorax  are  irregular.     Wyeomyia  smithii  Coq. 

II  The  Thorax  is  Without  Marks  or  Ornamentation 

(a)  The  segments  of  abdomen  are  narrowly  banded  at  their 
bases. 

1.  A  small  dark-brown  species;  abdominal  bands  wider  in 
the  middle  than  at  sides  except  on  seventh  segment, 
which  usually  has  a  narrow  band,  broad  at  the  sides, 
Aedes  fuscus  O.  S. 

2.  A  moderate-sized  brownish  species  with  the  bands  of 
abdomen  of  moderate  width,  Culex  pipiens  Linn. 

3.  A  somewhat  darker,  longer-legged  species,  with  very 
narrow,  regular  abdominal  bands,  Culex  salinarius  Coq. 

(b)  The  segments  of  the  abdomen  are  narrowly  banded  at  their 
apices  only. 

1.  A  small,  slight,  blackish  species,  Culex  territans,  Wlk. 

(c)  The  abdomen  has  no  bands  or  only  the  merest  indications  of 
them. 

1.  A  uniformly  dark-brown  species  of  moderate  size,  Culex 
melanurus  Coq. 

2.  Species  having  thorax  yellowish-brown,  somewhat 
polished,  with  a  thin,  bluish-gray  fresting,  Anopheles 
barberi  Coq. 

LARVAE 

Antennae  arising  from  the  sides  of  the  head;  antennae  not  pendant 

1.  No  siphon  or  breathing-tube  on  eighth  abdominal  segment,  Anopheles 

(2). 
A  siphon  or  breathing-tube  on  eighth  abdominal  segment  (3). 

2.  Antennae  yellowish;  tracheal  gills  moderate  in  size,  A.  punctipennis, 

A.  quadrimaculatus. 
Antennae  shorter,  brownish;  tracheal  gills  short,  A.  crucians. 


APPENDIX  231 

3.  Hair  tufts  on  thorax  and  abdomen  simple,  sparse  or  absent  (4). 
Thorax  and  abdomen  with  star-shaped  or  stellate  hair  tufts,  Urano- 

taenia  sapphirina. 

4.  Abdomen  with  four  tracheal  gills  at  tip  (5). 

Abdomen  with  two  tracheal  gills  only;  a  small  whitish  species,  with 
head  rounded  and  thorax  subquadrate,  Wyeomyia  smithii. 

5.  Antennae  arise  from  sides  of  anterior  part  of  head  (6). 

Antennae  arise  from  near  middle  of  sides  of  head;  the  mouth  brushes 
form  a  club  at  sides  of  mouth;  a  very  large  species,  Psorophora 
ciliata. 

6.  The  scales  of  the  eighth  abdominal  segment  are  separate  (8). 

The  scales  of  the  eighth  abdominal  segment,  5  to  8  in  number,  are 

arranged  on  a  band  (7). 
The  scales  are  replaced  by  a  series  of  chitinous  bars,  arranged  in  a 

single  row  (22). 

7.  The  anal  siphon  is  very  large  and  stout,  dilated  centrally;  antennae 

much  longer  than  head,  slender  with  an  even  outcurve  or  con- 
vexity, Psorophora  (J  anthinasoma)  sayi. 
The  anal  siphon  shorter,  stout,  dilated  nearer  the  base;  antennae 
nearly  straight  slender  and  shorter  than  head,  Psorophora  (Janthi- 
nasoma)  cohmibiae. 

8.  The  scales  are  not  more  than  16  in  number  and  form  a  small  patch  (9). 
The  scales  number  20  or  more  and  form  a  large  patch  (12). 

9.  Anna!  siphon  of  moderate  length,  three  times  as  long  as  wide,  or 

longer  (10). 
Anal  siphon  short,  less  than  three  times  as  long  as  wide  (11). 

10.  About  12  elongate  scales  in  a  single  row;  12-16  siphonal  spines,  each 

with  one  moderate-sized  tooth,  and  sometimes  a  few  very  small 

ones  below  it,  Aedes  fuscus. 
Scales  10-15,  in  partly  double  row,  tapering  apically;  siphonal  spines, 

14-18,  simple  or  with  2  or  3  teeth,  Aedes  vexans. 
Scales  7-12  in  patch;  a  small,  translucent  species,  feeding  at  bottom; 

tracheal  gills  very  long  and  slender,  Aedes  dupreei. 
Scales  6-7,  arranged  in  a  curve;  tracheal  gills,  long,  slender,  uniformly 

tapering,  Aedes  abserratus. 

11.  A  stout,  black  species;  the  thorax  white-banded;  antennal  tuft  com- 

posed of  many  hairs;  tracheal  gills  very  long,  Aedes  atlanticus. 
An  elongate,  slender,  gray  species;  antennal  tuft  a  single  bristle; 

tracheal  gills  short,  Aedes  triseriatus. 
A  large  robust,  light  species;  anal  siphon  bottle-shaped,  outer  half 

linear;   anal  gills  slightly  longer  than  width  of  ninth  segment, 

Mansonia  perturbans. 

12.  Anal  siphon  short,  not  much  more  than  twice  as  long  as  broad  (13). 
Anal  siphon  moderate,  from  2lA  to  3f£  times  as  long  as  broad  (15). 
Anal  siphon  long,  not  less  than  4  times  as  long  as  broad  (21). 

13.  Stout,  compact  larva;  antennal  tuft  of  several  hairs  (14). 

Long,  slender  larva;  antennal  tuft  of  1  or  2  hairs;  25-35  scales  in 
patch;  17-21  siphonal  spines,  with  2  or  3  long  teeth  at  base,  Aedes 
atropalpus. 

16 


232  MOSQUITO  ERADICATION 

14.  Scales   14-22,  with  stout  apical  and  slender  lateral  spines;   13-18 

siphonal  spines  with  2  or  3  small  teeth  sometimes  simple;  fresh 

water,  Aedes  trivittatus. 
Scales  16-22,  with  rounded  apex  and  slender  lateral  spines;  12-16 

siphonal  spines  with  1-4  small  teeth  on  both  sides;  head  maculate; 

salt  marsh,  Aedes  taeniorhynchus. 
Scales  20-40,  with  stout  apical  and  slender  lateral  spines;   16-24 

siphonal  spines  with  1-5  small  teeth;  head  generally  immaculate; 

salt  marsh,  Aedes  sollicitans. 

15.  Scales  rather  broad  (16). 
Scales  elongate  (17). 

16.  Scales  35-40,  with  3  stout  apical  and  smaller  lateral  spines;  16-20 

siphonal  spines  with  1-3  small  teeth;  head  maculate;  salt  marsh, 
Aedes  cantator. 
Scales  25-50,  with  one  very  stout  apical  and  slender  lateral  spine; 
16-22  siphonal  spines,  with  1-2  large  and  4-6  smaller  teeth  on 
basal  half;  head  immaculate;  fresh  water  form,  Aedes  stimulans. 

17.  Only  the  terminal  segment,  with  a  dorsal  plate  or  ring  (18). 

18.  Antennae  not  specially  marked  or  colored  (19). 

Antennae  prominent,  white  at  base,  dark  at  tip,  Aedes  aurifer. 

19.  Moderate-sized  species  (20). 

Very  large  larva;  scales  28-34,  with  long  apical  and  slender  lateral 
spines;  siphonal  spines  17-22,  with  4  or  5  large  teeth  basally,  Aedes 
grossbecki. 

20.  Scales  25-50  with  short  apical  and  very  short  lateral  spines;  siphonal 

spines  16-20,  with  1-2  teeth  at  base,  one  usually  very  large,  Aedes 
hirsuteron. 
Scales  25-50,  with  small  apical  and  smaller  lateral  spines;   16-24 
siphonal  spines  with  4-5  serrations  on  basal  half;  antenna  dark  at 
tip,  Aedes  canadensis. 

21.  Antennal  tuft  above  the  middle. 

Anal  siphon  of  moderate  length,  sides  a  little  inflated;  tracheal  gills 

moderately  long,  Culex  pipiens. 
Anal  siphon  very  long,  rather  slender  and  slightly  tapering  to  tip; 

head  narrower  than  thorax;  tracheal  gills  short,  Culex  salinarius. 
Anal  siphon  very  long  and  slender;  a  little  constricted  centrally;  head 

as  wide  as  thorax;  tracheal  gills  moderate  or  long,  Culex  lerritans. 
Antennal  tuft  below  middle. 

Scales  24-30,  antenna  not  arising  from  an  offset,  Aedes  abfitchii. 
Anal  siphon  of  moderate  length;  tracheal  gills  rather  long,  Culex 

restuans. 
Anal  siphon  5  times  as  long  as  widest  diameter;  antennae  dark  at  tip, 

Aedes  fitchii. 

22.  A  bronzed,  brown  larva,  with  rather  long,  moderately  stout,  black 

breathing  tube,  Culex  melanurus. 


APPENDIX  B 
APPROVED  ANTI-MOSQUITO  ORDINANCE 

The  following  ordinance,  prepared  in  connection  with  the  joint,  coop- 
erative anti-malaria  demonstration  work  of  the  U.  S.  Public  Health 
Service  and  the  International  Health  Board,  has  been  adopted  by  a  large 
number  of  cities,  towns  and  villages  in  various  parts  of  the  United  States, 
and  has  proven  uniformly  satisfactory: 

ORDINANCE  FOR  THE  PREVENTION  OF  MOSQUITO  BREEDING 

IN  THE 


Section  1— It  shall  be  unlawful  to  have,  keep,  maintain,  cause  or  permit, 

within  the  (incorporated)  limits  of 

any  collection  of  standing  or  flowing  water  in  which  mosquitoes  breed  or  are 
likely  to  breed,  unless  such  collection  of  water  is  treated  so  as  effectually  to 
prevent  such  breeding. 

Section  2.— Any  collections  of  water  considered  by  Section  1  of  this 
ordinance  shall  be  held  to  be  those  contained  in  ditches,  pools,  ponds, 
excavations,  holes,  depressions,  open  cess-pools,  privy  vaults,  fountains, 
cisterns,  tanks,  shallow  wells,  barrels,  troughs  (except  horse  troughs  in 
frequent  use),  urns,  cans,  boxes,  bottles,  tubs,  buckets,  defective  house  roof 
gutters,  tanks  of  flush  closets  or  other  similar  water  containers. 

Section  3.— The  method  of  treatment  of  any  collections  of  water,  that  are 
specified  in  Section  2,  directed  toward  the  prevention  of  breeding  of  mos- 
quitoes, shall  be  approved  by  the  accredited  health  officer,  and  may  be  any 
one  or  more  of  the  following: 

(a)  Screening  with  wire  netting  of  at  least  16  meshes  to  the  inch  each 
way  or  with  any  other  material  which  will  effectually  prevent  the  ingress 
or  egress  of  mosquitoes. 

(b)  Complete  emptying  every  seven  (7)  days  of  unscreened  containers, 
together  with  their  thorough  drying  or  cleaning. 

(c)  Using  a  larvicide  approved  and  applied  under  the  direction  of  the 
health  officer. 

(d)  Covering  completely  the  surface  of  the  water  with  kerosene,  petroleum 
or  paraffin  oil  once  every  seven  (7)  days. 

(e)  Cleaning  and  keeping  sufficiently  free  of  vegetable  growth  and  other 
obstructions,  and  stocking  with  mosquito-destroying  fish. 

(J)  Filling  or  draining  to  the  satisfaction  of  the  health  officer. 

(<7)  Proper  disposal,  by  removal  or  destruction,  of  tin  cans,  tin  boxes, 
broken  or  empty  bottles  and  similar  articles  likely  to  hold  water. 

Section  4.— The  natural  presence  of  mosquito  larvae  in  standing  or  running 
water  shall  be  evidence  that  mosquitoes  are  breeding  there,  and  failure  to 

233 


234  MOSQUITO  ERADICATION 

prevent  such  breeding  within  three   (3)  days  after  notice  by  the  health 
officer  shall  be  deemed  a  violation  of  this  ordinance. 

Section  5. — Should  the  person  or  persons  responsible  for  conditions  giving 
rise  to  the  breeding  of  mosquitoes  fail  or  refuse  to  take  necessary  measures 
to  prevent  the  same,  within  three  (3)  days  after  due  notice  has  been  given 
to  them,  the  health  officer  is  hereby  authorized  to  do  so,  and  all  necessary 
cost  incurred  by  him  for  this  purpose  shall  be  a  charge  against  the  property- 
owner  or  other  person  offending,  as  the  case  may  be. 

Section  6. — For  the  purpose  of  enforcing  the  provisions  of  this  ordinance, 
the  health  officer,  or  his  duly  accredited  agent,  acting  under  his  authority, 
may  at  all  reasonable  times  enter  in  and  upon  any  premises  within  his 
jurisdiction;  and  any  person  or  persons  charged  with  any  of  the  duties 
imposed  by  this  ordinance  failing,  within  the  time  designated  by  this 
ordinance,  or  within  the  time  stated  in  the  notice  of  the  health  officer,  as  the 
case  may  be,  to  perform  such  duties,  or  to  carry  out  the  necessary  measures 
to  the  satisfaction  of  the  health  officer,  shall  be  deemed  guilty  of  a  separate 
violation  of  this  ordinance. 

Section  7. — Any  person  who  shall  violate  any  provision  of  this  ordinance 
shall  on  each  conviction  be  subject  to  a  fine  of  not  less  than  One  Dollar 
($1.00)  or  more  than  Twenty-five  Dollars  ($25.00),  in  the  discretion  of  the 
court. 

Section  8. — All  ordinances  or  parts  of  ordinances  in  conflict  with  this 
ordinance  are  hereby  repealed,  and  this  ordinance  shall  be  in  full  force  and 

effect days  after  its  approval. 

Adopted  this day  of 


Approved  this day  of . 


APPENDIX  C 
SUGGESTED   ANTI-MOSQUITO   LEAFLET   FOR   CAMPAIGN 

EDUCATIONAL  WORK 

The  experience  of  the  writer  has  been  that  only  a  very  small  proportion 
of  the  inhabitants  of  the  average  American  municipality  have  any  adequate 
idea  as  to  where  and  in  what  manner  mosquito-breeding  takes  place  about 
homes,  and,  consequently,  a  vast  amount  of  mosquito  production  can  be 
eliminated  if  the  citizens  are  made  cognizant  of  a  few  simple  facts  on  the 
subject  and  persuaded  to  give  their    co-operation. 

The  following  matter  is  not  presented  as  a  model  essay  on  the  subject. 
It  is  submitted  only  to  give  some  idea  of  the  facts  which,  in  the  opinion  of 
the  writer,  ought  to  be  given  the  people  of  a  town  engaging  in  mosquito 
control  work,  in  order  to  obtain  their  intelligent  co-operation.  It  is  believed 
that  the  expense  of  printing  and  distributing  such  a  leaflet  will  be  more 
than  repaid  by  the  resulting  assistance  of  the  informed  citizens. 

YOUR  PART  IN  THE  CITY1  ANTI-MOSQUITO 

CAMPAIGN 

How  to  Get  Rid  of  Mosquitoes  About  The  Home 

Mosquitoes  Spread  Malaria ;  Mosquitoes  Can  Be  Eliminated. — In  view 
of  the  proven  fact  that  mosquitoes  are  solely  responsible  for  the  spread 
of  malaria  and  other  serious  diseases  and  of  the  further  proven  fact  that 
mosquitoes  can  be  done  away  with  in  any  ordinary  community  by  intelligent 
effort,  the  City1  authorities  have  decided  this  year  to  initiate  an  antimos- 

quito  campaign  in 2  and  an  appropriation  has  already 

been  made  for  the  purpose. 

People  Must  Lend  Their  Aid;  Your  Job  and  the  City's.1 — In  order  that 
the  campaign  be  a  success,  it  is  absolutely  necessary  that  every  citizen  do 
his  part.  The  city  is  prepared  to  prevent  mosquito-breeding  in  streams, 
ponds,  swamps  and  other  natural  breeding-places  throughout  the  City,1  as 
well  as  in  roads,  streets,  parks  and  other  public  places,  but  the  private 
citizen  must  prevent  mosquito-breeding  on  his  own  premises,  insofar  as  such 
breeding  is  a  result  of  his  own  activities  or  his  own  negligence.  This  duty 
is  imposed  upon  the  citizen  by  City1  ordinance. 

Purpose  of  This  Leaflet  Is  To  Tell  You  How  To  Do  Your  Part.— This 
leaflet  is  distributed  by  the  City1  with  the  object  of  aiding  citizens  in  doing 

1  Substitute  Town  or  Village,  where  necessary. 

2  Insert  name  of  place. 

235 


236  MOSQUITO  ERADICATION 

this  duty,  by  telling  them  something  about  the  breeding-habits  of  mosquitoes 
and  about  practical  and  easy  ways  to  prevent  such  breeding. 

It  should  be  fully  understood  that  there  is  absolutely  no  doubt  that 
mosquitoes  spread  malaria  and  other  diseases,  nor  that  mosquitoes  can  be 
virtually  done  away  with  in  any  ordinary  community.  The  work  on  the 
Panama  Canal  Zone  and  in  numerous  other  places  has  fully  demonstrated 
the  truth  of  these  statements. 

Some  Common  Breeding-places  about  the  Average  Home. — Mosquitoes 
breed  only  in  standing  or  slowly  running  water.  The  belief  that  they 
breed  in  grass,  bushes  or  other  such  places  was  exploded  many  years  ago. 
Hence,  if  we  are  to  do  away  with  mosquitoes,  we  must  either  do  away  with 
the  water  or  else  take  steps  to  prevent  them  from  breeding  in  it.  These 
other  steps  include  screening,  oiling,  stocking  with  mosquito-destroying 
fish,  etc.  Which  of  these  measures  to  take  in  any  particular  case  depends 
upon  the  circumstances,  as  will  be  explained  directly. 

The  usual  breeding-places  of  mosquitoes  about  homes  are:  cisterns; 
barrels,  tubs  and  buckets  of  water;  shallow  wells;  pools  of  water  from  rains, 
leaky  pipes,  etc.;  tin  cans,  bottles,  etc.,  that  hold  water;  water-troughs; 
cess-pools  that  are  not  tightly  covered;  certain  types  of  privies  that  mos- 
quitoes can  enter;  stopped-up  roof  gutters,  etc.  In  fact,  any  collection 
of  water  that  a  mosquito  can  get  to  is  likely  to  become  a  breeding-place. 

How  to  Handle  the  Various  Breeding-places.— The  best  measure  to  take 
to  stop  breeding  in  any  certain  case  depends  upon  the  nature  of  the  breeding- 
place.  Thus,  where  possible,  pools  of  water  should  be  drained;  if  they 
cannot  be  drained,  they  should  be  oiled  (that  is,  covered  with  a  visible 
film  of  kerosene  or  other  light  mineral  oil)  once  a  week  or  else  stocked  with 
mosquito-destroying  fish,  which  may  be  obtained  from  the  City.1  Surface 
cisterns  should  be  screened  in  such  manner  that  they  will  be  mosquito- 
proof;  underground  cisterns  should  be  tightly  covered  or  else  stocked  with  a 
few  mosquito-destroying  fish.  Barrels,  tubs  and  buckets  of  water  should 
either  be  screened  with  burlap  or  netting  or  else  oiled  once  a  week  or  else 
emptied  and  thoroughly  dried  out  once  a  week.  The  best  way  to  handle 
shallow  wells  is  to  stock  each  with  two  or  three  mosquito  destroying  fish, 
which  will  in  no  way  injure  the  water.  Tin  cans,  bottles,  etc.,  should 
either  be  buried  or  hauled  away.  Water-troughs  should  be  emptied  and 
then  dried  out  thoroughly  once  a  week.  Cess-pools,  etc.,  should  be  tightly 
covered  and  mosquito-breeding  privies  should  be  well  oiled,  after  which  the 
lids  should  be  kept  closed  down,  whenever  the  privy  is  not  in  use.  Stopped- 
up  roof  gutters  should  be  cleaned  out  and,  where  necessary,  re-hung. 

Make  Inspection  of  Your  Premises  Once  Every  Week. — The  City1 
expects  citizens  to  eliminate  or  otherwise  take  care  of  any  and  all  of  the  above- 
mentioned  classes  of  breeding-places  that  may  be  on  their  premises.  One 
of  the  best  ways  of  doing  this  is  for  each  citizen  to  make  a  close  inspection 
of  his  premises  at  least  once  a  week,  and  particularly  after  heavy  rains, 
emptying  all  unscreened  receptacles  containing  water  or  else  oiling  or  other- 
wise treating  them,  paying  particular  attention  to  tin  cans,  etc.  The  reason 
for  making  the  inspection  weekly  is  that  it  requires  only  a  little  more  than  a 
week  for  the  full-fledged  mosquito  to  develop  from  the  egg. 

1  Substitute  Town  or  Village,  where  necessary. 


APPENDIX  237 

How  the  City1  Helps  You  To  Do  Your  Part. — An  aquarium  of  mosquito- 
destroying  fish  is  kept  up  by  the  City1  anti-mosquito  forces  for  the  purposes 
of  supplying  all  citizens  who  may  have  use  for  them.  These  fish  are  very 
effective  for  cisterns,  shallow  wells  and  more  or  less  permanent  pools  which 
it  is  impracticable  to  drain.  In  order  for  the  fish  to  work  effectively,  how- 
ever, it  is  necessary  to  keep  the  pool  free  from  vegetation. 

The  City1  anti-mosquito  forces  will  be  glad  to  help  willing  citizens  in  any 
other  manner  possible.  The  director  of  the  campaign  will  at  all  times  take 
pleasure  in  advising  such  citizens  as  to  the  best  methods  of  solving  their 
problems.  Citizens  who  refuse  or  neglect  to  keep  their  premises  free  from 
mosquito-breeding  will  receive  scant  consideration,  however.  Periodical 
inspections  will  be  made  of  every  home  in  the  City,1  and  persons  who  fail 
to  comply  with  the  law  will  be  prosecuted.  The  ordinances  provide  for  a 
fine  of  from  SI. 00  to  $25.00  for  each  violation. 

No  Fun  Raising  Mosquitoes;  They  Cost  City1  Real  Money. — However,  it 
is  the  belief  of  the  City1  authorities  that  few,  if  any,  prosecutions  will  be 

necessary   in 2     There  is  no  pleasure  to  be  derived 

from  raising  mosquitoes,  and  mosquito-farms  do  not  bring  any  profit;  on 
the  contrary,  as  already  stated,  mosquitoes  spread  malaria  and  other 
diseases,  which  yearly  cause  a  vast  amount  of  suffering  and  expense.  It  is 
figured  by  health  experts  that  each  case  of  malaria  costs  from  $15  to  $20 
in  loss  of  time,  loss  of  efficiency,  medicines  and  physicians'  bills.     As  it  is 

estimated  that  there  were, cases  of  malaria  in 2 

last  year,  it  will  easily  be  seen  that  it  is  to  the  interest  of  every  citizen  to 
help  cut  down  this  big  annual  community  expense.  In  addition  to  the 
sickness  they  cause,  the  annoyance  occasioned  by  mosquitoes  is  well  known 
to  every  one,  and  of  itself  would  make  it  well  worth  while  to  do  away  with 
the  mosquito. 

Raising  Mosquitoes  Almost  As  Bad  As  Raising  "Cooties." — But  there  is 
another  reason  why  each  citizen  should  do  his  utmost  to  prevent  mosquito- 
breeding  about  his  home.  That  is  self-respect.  A  man  who  raises  "cooties" 
on  his  person  is  regarded  as  slothful  and  unclean.  The  day  is  not  far  dis- 
tant when  a  man  who  raises  mosquitoes  on  his  premises  will  be  regarded 
as  equally  slothful  and  unclean. 


Director, 

Anti-mosquito  Campaign. 


1  Substitute  Town  or  Village,  where  necessary. 

2  Insert  name  of  place. 


APPENDIX  D 


BIBLIOGRAPHY 


The  following  publications  have  been  consulted  in  the  preparation  of  this 
work: 

Transactions  of  the  First  Annual  Conference  of  Sanitary  Engineers  and 
Other  Officers  of  the  Public  Health  Service  Directing  Anti-malaria  Campaign, 
Public  Health  Bulletin  No.  104,  U.  S.  Public  Health  Service,  Washington, 
D.  C,  1919. 

Transactions  of  the  Second  Annual  Anti-malaria  Conference  of  Sanitary 
Engineers  and  Others  Engaged  in  Malaria  Field  Investigations  and  Mosquito 
Control.  Public  Health  Bulletin  No.  155,  U.  S.  Public  Health  Service, 
Washington,  D.  C,  1921. 

Mosquito  Control  About  Cantonments  and  Ship-yards,  by  J.  A.  Le 
Prince,  Reprint  No.  511,  U.  S.  Public  Health  Service,  1919. 

Anopheles  Crucians  Wied.  As  an  Agent  in  Malaria  Transmission,  by 
C.  W.  Metz.,  Reprint  No.  536,  U.  S.  Public  Health  Sen-ice,  1919. 

Malaria:  A  Public  Health  and  Economic  Problem  in  the  United  States, 
by  John  W.  Trask,  Reprint  No.  382,  U.  S.  Public  Health  Service,  1917. 

Malaria  Control:  Drainage  as  an  Anti-malarial  Measure,  by  J.  A.  Le- 
Prince,  Reprint  No.  258,  U.  S.  Public  Health  Service,  1915. 

Control  of  Malaria:  Oiling  as  an  Anti-mosquito  Measure,  by  J.  A. 
LePrince,  Reprint  No.  260,  U.  S.  Public  Health  Service,  1915. 

Filariasis  in  Southern  United  States,  by  Edward  Francis,  Hygienic 
Laboratory  Bulletin  No.  117,  U.  S.  Public  Health  Service,  1919. 

Field  Identification  of  Malaria-carrying  Mosquitoes,  by  Ernest  A.  Sweet, 
Supplement  No.  32,  U.  S.  Public  Health  Service,  1918. 

Anopheles  Crucians:  Habits  of  Larvae  and  Adults,  by  C.  W.  Metz, 
Reprint  No.  495,  U.  S.  Public  Health  Service,  1919. 

Observations  on  the  Food  of  Anopheles  Larvae,  by  C.  W.  Metz.,  Reprint 
No.  549,  U.  S.  Public  Health  Service,  1919. 

The  Malaria  Problem  of  the  South,  by  H.  R.  Carter,  Reprint  No.  552, 
U.  S.  Public  Health  Service,  1919. 

The  Relations  of  the  Railroads  in  the  South  to  the  Problem  of  Malaria  and 
Its  Control,  by  R.  C.  DERrvAtrx,  Reprint  No.  480,  U.  S.  Public  Health 
Service,  1918. 

Use  of  Dynamite  in  Anti-malarial  Drainage  Operations,  by  J.  K.  Hoskins 
and  W.  E.  Hardenburg,  Reprint  No.  493,  U.  S.  Public  Health  Service,  1919. 
Malaria:  Lessons  on  Its  Cause  and  Prevention,  by  H.  R.  Carter,  Supple- 
ment No.  18,  U.  S.  Public  Health  Service,  1918. 

What  the  Farmer  can  do  to  Prevent  Malaria,  by  R.  H.  Von  Ezdorf, 
Supplement  No.  11,  U.  S.  Public  Health  Service,  1914. 

Demonstrations  of  Malaria  Control,  by  R.  H.  Von  Ezdorf,  Reprint  No. 
328,  U.  S.  Public  Health  Service,  1918. 

238 


APPENDIX  239 

Some  Aspects  of  Malaria  Control  Through  Mosquito  Eradication,  by 
C.  W.  MeTZ,  Reprint  No.  500,  U.  S.  Public  Health  Service,  1919. 

Anopheline  Surveys:  Methods  of  Conduct  and  Relation  to  Anti-malarial 
Work,  by  R.  H.  Von  Ezdorf,  Reprint  No.  272,  U.  S.  Public  Health  Service, 
1918. 

Prevention  of  Malaria:  Suggestions  on  How  to  Screen  the  Home  to 
Keep  Out  Effectively  the  Mosquitoes  which  Spread  Disease,  by  R.  H.  "Von 
Ezdorf,  Reprint  No.  170,  U.  S.  Public  Health  Service,  1916. 

Malaria  Control:  A  Report  of  Demonstration  Studies  Conducted  in 
Urban  and  Rural  Sections,  by  R.  C.  Derivatjx,  H.  A.  Taylor  and  T.  D. 
Haas,  Public  Health  Bulletin  No.  88,  U.  S.  Public  Health  Service,  1917. 

Malaria  Control:  Results  Obtained  by  a  Local  Community  Following 
Anti-mosquito  Demonstration  Studies  by  the  United  States  Public  Health 
Service  in  co-operation  with  the  International  Health  Board,  by  J.  E. 
Sparks,  R.  C.  Derivaux  and  H.  A.  Taylor,  Reprint  No.  476,  U.  S.  Public 
Health  Service,  1918. 

Anti-malarial  Measures  for  Farm-houses  and  Plantations,  by  H.  R. 
Carter,  Reprint  No.  105,  U.  S.  Public  Health  Service,  1919. 

Fishes  in  Relation  to  Mosquito  Control  in  Ponds,  by  S.  F.  Hildebrand, 
Bureau  of  Fisheries  Document  No.  874,  U.  S.  Bureau  of  Fisheries,  Wash- 
ington, D.  C,  1919. 

Notes  on  the  Life  History  of  the  Minnows,  Gambusia  Affinis  and  Cypri- 
nodon  Variegatus,  by  S.  F.  Hildebrand,  Bureau  of  Fisheries  Docuvu -nt 
No.  857,  U.  S.  Bureau  of  Fisheries,  1917. 

Tile  Drainage  on  the  Farm,  by  A.  G.  Smith,  Farmers'  Bulletin  No.  524, 
U.  S.  Department  of  Agriculture,  1917. 

Trenching  Machinery  Used  for  the  Construction  of  Trenches  for  Tile 
Drains,  by  D.  L.  Yarnell,  Farmers'  Bulletin  No.  698,  U.  S.  Department  of 
Agriculture,  1915. 

The  Mosquitoes  of  New  Jersey  and  Their  Control,  by  Thomas  J.  Headlee, 
Bulletin  No.  276,  New  Jersey  Agricultural  Experiment  Stations,  New  Bruns- 
wick, N.  J.,  1915. 

Some  Recent  Advances  in  Knowledge  of  the  Natural  History  and  the 
Control  of  Mosquitoes,  by  Thomas  J.  Headlee,  Bulletin  No.  306,  New 
Jersey  Agricultural  Experiment  Stations,  New  Brunswick,  N.  J.,  1916. 

A  Biological  Study  of  the  More  Important  of  the  Fish  Enemies  of  the 
Salt  Marsh  Mosquitoe's,  by  F.  E.  Chidester,  Bulletin  No.  300,  New  Jersey 
Agricultural  Experiment  Stations,  New  Brunswick,  N.  J.,  1916. 

"Field  Experiments  in  Malaria  Control,"  by  Wickliffe  Rose,  American 
Medical  Association,  Chicago,  1919. 

The  Importance  of  Malaria  from  A  Public  Health  and  Economic  Stand- 
point, by  W.  S.  Leathers,  Southern  Medical  Journal,  Birmingham,  Ala., 
1918. 

"Preventive  Medicine  and  Hygiene,"  by  Milton  J.  Roesnatj,  D. 
Appleton  &  Co.,  New  York  and  London,  1918. 

"A  Plea  and  a  Plan  for  the  Eradication  of  Malaria  Throughout  the 
Western  Hemisphere,"  by  Frederick  L.  Hoffman,  Prudential  Insurance 
Company  of  America,  Newark,  N.  J.,  1917. 

"The  Use  of  Explosives  in  Making  Ditches,"  Institute  of  Makers  of 
Explosives,  New  York,  1917. 


240  MOSQUITO  ERADICATION 

"Blasters'  Hand-book,"  E.  I.  duPont  de  Nemours  &  Company,  Wil- 
mington, Del.,  1918. 

"Myers'  Spray  Pumps,"  F.  E.  Myers  &  Bro.,  Ashland,  Ohio. 

"Calco  Automatic  Drainage  Gates,"  California  Corrugated  Culvert 
Company,  West  Berkeley,  Calif. 

Other  publications  on  mosquitoes  and  kindred  topics  include: 

"The  Mosquitoes  of  North  and  Central  America  and  the  West  Indies," 
by  L.  O.  Howard,  H.  G.  Dyar  and  Frederick  Knab,  Carnegie  Institution, 
Washington,  D.  C. 

"A  Monograph  of  the  Culicidae  of  the  World,"  by  F.  V.  Theobald, 
British  Museum,  London,  England. 

"Mosquito  Control  in  Panama,"  by  J.  A.  LePrince  and  A.  J.  Orenstein, 
New  York,  1916. 


INDEX 


Abercrombie,  216,  217 
Abramis  chrysolenca,  183 
Acilius  sulcatus,  211 
Aedes  calopus,  9,  34 
canadensis,  42 
cantator,  48 
sollicitans,  44 
taenierhynchus,  48 
vexans,  42 
Aegilitis  semipalmata,  211 
Aeschna,  211 

Agamodistomum  martiranoi,  211 
Agamomermis  culicis,  211 
Albany,    Ga.,    particulars    of    anti- 
mosquito  work  at,  64 
Alexandria,  La.,  war  anti-mosquito 

work  at,  59 
Alexandria,  Va.,  war  anti-mosquito 

work  at,  59 
Algae,  188 

Alto,     Tex.,     particulars     of     anti- 
mosquito  work  at,  64 
Amblystoma  opacum,  211 
Americus,    Ga.,    war   anti-mosquito 

work  at,  59 
Anas  platyrhynches,  211 
Animals      as      protection      against 

mosquitoes,  214 
Anniston,    Ala.,    war   anti-mosquito 

work  at,  59 
Anopheles  albimanus,  25 
argyritarsis,  25 
claviger,  25 
costalis,  25 
crucians,  25,  29 
intermedium,  25 
maculipennis,  25 
occidentalis,  25,  32 
pseudomaculipes,  25 
pseudopunctipennis,  25 
punctipennis,  25,  30 


Anopheles     albimanus,     quadrima- 
culatus,  25,  28 

sinensis,  25 

tarsimaculate,  25 
Anophelinae,  in  general,  25 

identification  of,  25 
Anti-mosquito  campaign  costs,  63 

campaign  leaflet,  235 

ordinance,  233 
Applying  oil,  other  methods  of,  1G7 
Aquarium,  need  for,  183 
Articles,  texts  for,  92 
Ashburn,  11 

Athens,    Tex.,    particulars    of    anti- 
mosquito  work  at,  64 
Atlanta,     Ga.,     war     anti-mosquito 

work  at,  59 
Augusta,    Ga.,    war    anti-mosquito 
work  at,  59 

B 

Bamberg,  S.  C,  particulars  of  anti- 
mosquito  work  at,  64 

Barber  and  Hayne,  163 

Barred  killifish  the,  176 

Bastrop,  La.,  particulars  of  anti- 
mosquito  work  at,  64 

Bat,  the,  as  a  mosquito-destroyer, 
210 

Batesville,  Miss.,  particulars  of 
anti-mosquito  work  at,  64 

Baton  Rouge,  La.,  particulars  of 
anti-mosquito  work  at,  64 

Bauxite,  Ark.,  demonstration  at,  56 

Beginning  of  mosquito  control,  the, 
51 

Bibliography,  238 

Biloxi,  Miss.,  anti-mosquito  work  at, 
59 

Bishop,  133,  162 

Blasting  ditches,  113 

Boom,  to  prevent  escape  of  oil,  192 

Breeding-places  about  homes,  83 


241 


242 


INDEX 


British  Guiana,  malaria  mortality 
in,  7 

British  Honduras,  malaria  mortality 
in,  7 

Brownsville,  Tenn.,  particulars  of 
anti-mosquito  work  at,  64 

Bryan,  Tex.,  particulars  of  anti- 
mosquito  work  at,  64 


C 


Cairo,     Ga.,     particulars     of     anti- 
mosquito  work  at,  64 

Calco  gate,  the,  153 

Calvert,    Tex.,    particulars   of   anti- 
mosquito  work  at,  64 

Cameron,  Tex.,  particulars  of  anti- 
mosquito  work  at,  64 

Campbell,  210 

Camphor,  spirits  of,  as  a  mosquito 
repellent,  215 

Carroll,  153 

Carter,  6,  7,  55,  196,  198,  203,  204, 
223 

Central  of  Georgia  Railway,  malaria 
appropriation,  58 

Ceylon,  malaria  mortality  in,  7 

methods  of  mosquito  control  in, 
224 

Chandeleur    Islands,    screening    at, 
204 

Charleston,     Miss.,     particulars    of 
anti-mosquito  work  at,  64 

Charleston,  S.  C,  war  anti-mosquito 
work  at,  59 

Charlotte,  N.  C,  war  anti-mosquito 
work  at,  59 

Chattanooga,       Tenn.,       war    anti- 
mosquito  work  at,  59 

Chester,  S.  C,  particulars  of  anti- 
mosquito  work  at,  64 

Chidester,  183,  211 

Chiroptera,  210 

Choetura  pelagica,  211 

Chordeiles  virginianus,  211 

Citronella,    oil    of,    as    a    mosquito 
repellent,  215 

Coffeeville,     Miss.,     particulars     of 
anti-mosquito  work  at,  64 


Columbia,  S.  C,  war  anti-mosquito 

work  at,  59 
Columbus,   Ga.,  war  anti-mosquito 

work  at,  59 
Columbus,     Miss.,     particulars     of 
anti-mosquito  work  at,  64 
Community  measures  in  rural  areas, 

225 
Complaint  bureau,  88 
Complaint  form,  90 
Control   measures   about  the  home. 

221 
Co-operation,  obtaining,  76,  93 
Cordilura  haemorhoidalis,  211 
Corethra,  211 
Corporations,      aid      anti-mosquito 

work,  61 
Cost  records,  95 

Costa  Rica,  malaria  mortality  in,  7 
Costs  of  blasting  ditches,  116 

of  hand  ditching,  110,  111 

of  machine  ditching,  119,  144 

of  maintenance,  124 

of  tile  drainage,  131 
Craig,  11 

Crangon  vulgaris,  211 
Creosote,  as  a  larvicide,  162 
Crithidia  fasciculata,  211 
Crossett,  Ark.,  demonstration  at,  56 
Cuba,  malaria  mortality  in,  7 
Culex  fatigans,  11,  13,  36 

pipiens,  39 

restuans,  40 

salinarius,  49 
Culicinae,  the,  32 
Cyprinodon  calaritanus,  183 

variegatus,  180 


D 


Dallas,  Tex.,  war  anti-mosquito 
work  at,  59 

Demopolis,  Ala.,  particulars  of  anti- 
mosquito  work  at,  64 

Dengue,  10,  11,  14 

Derivaux,  77,  206. 

Dermott,  Ark.,  demonstration  at,  56 

Diemyctylus  tortosus,  211 

Dikes,  construction  of,  145 


INDEX 


243 


Diking,  in  general,  144 

Diplocystis,  211 

Discoglossus  pictus,  211 

Distribution  of  malaria,  5 
of  oil,  169 

Ditch  construction,  106,  140 

Ditching  by  dynamite,  113 
by  hand,  107,  110,  142 
by  machinery,  117,  143 
costs,   110,   111,   116,   124,   131, 

144 
required  per  acre  of  marsh,  141 

Dothan,    Ala.,    particulars   of   anti- 
mosquito  work  at,  64 

Drainage,  in  general,  99 
problems,  102 

Drip-cans,  165 

Duck-weed,  190 

Dyar,  32,  43 

Dyersburg,     Tenn.,     particulars    of 
anti-mosquito  work  at,  64 

Dytiscus  marginalis,  211 

E 

Eggs,  mosquito,  18,  27,  28, 34,  35,  37, 

42,  43,  46 
Eldorado,  Ark.,  particulars  of  anti- 
mosquito  work  at,  64 
Electric  Mills,  Miss.,  demonstration 

at,  55 
Emesa  longipes,  211 
Eptesicus  fuscus,  212 
Equipment  and  materials,  82 
Erythemis  simplicicollis,  211 
Estimate  of  cost,  the,  71 
Eufala,    Ala.,    particulars    of    anti- 
mosquito  work  at,  64 
Expedients,  auxiliary,  209 
Expenditures  record,  the,  96 
Exterminative  measures,  direct,  210 


Farmville,  N.  C,  particulars  of 
anti-mosquito  work  at,  64 

Fayetteville,  N.  C,  war  anti- 
mosquito  work  at,  59 

Filariae,  13 

Filariasis,  11,  14 

Filling,  138,  144 


Finlay,  51 

Fish  control,  in  general,  172 

procedure  in,  183 
Flight,    distances  of  mosquitoes,  17, 

29,  36,  37,  42,  44 
Flint,  51 
Florence,    Ala.,    war    anti-mosquito 

work  at,  59 
Foes,  animal,  of  mosquitoes,  211 
Fordyce,   Ark.,   particulars  of  anti- 
mosquito  work  at,  64 
Fort  Worth,  Tex.,  war  anti-mosquito 

work  at,  59 
Fresh- water  killy,  the,  179 
Fuchs,  146,  149,  150,  153 
Funds,  raising,  74 

handling  of,  75 
Fundulus  diaphanous,  179 

heteroclitus,  176 

majalis,  179 

notatus,  181 

notii,  181 

G 

Gambusia  affinis,  175 

Gantt's  Quarry,  Ala.,  particulars  of 

anti-mosquito  work  at,  64 
Gies,  148,  156 
Girardinus  caudimaculatus,  183 

poeciloides,  183 
Gold-fish,  the,  182 
Goldsboro,    N.    C.,    particulars    of 

anti-mosquito  work  at,  64 
Gorgas,  51,  53 
Gorman,  132 
Graham,  11 
Greenville,    N.    C.,    particulars    of 

anti-mosquito  work  at,  64 
Greenville,  S.  C.,  war  anti-mosquito 

work  at,  59 
Guatemala,    yellow  fever   outbreak 

suppressed,  53 
Gulfport,   Miss.,  war  anti-mosquito 

work  at,  59 
Gunasekara,     224 


H 


Haas,  206 


244 


INDEX 


Hamburg,  Ark.,  demonstration  at, 
56 

Haptochilus,  183 

Harboring-places  of  the  mosquito, 
212,  213 

Harrassing  the  mosquito,  213 

Hartsville,  S.  C,  particulars  of  anti- 
mosquito  work  at,  64 

Hattiesburg,  Miss.,  war  anti- 
mosquito  work  at,  59 

Havana,  freed  of  yellow  fever,  51 

Hayne  and  Barber,  163 

Headlee,  15,  19,  21,  24,  43,  46,  140, 
141,  142,  144,  146,  150, 
151 

Hearne,  Tex.,  particulars  of  anti- 
mosquito  work  at  64, 

Hematocytozoa,  1 

Herpetomonous  algeriense,  211 

Hildebrand,  173,  181,  183,  184,  187, 
188,  190 

Hirundo  erythrogasta,  211 

Historical  aspects  of  mosquito 
control,  50 

Hoffman,  8,  211 

Horpopeza  obliterate,  211 

Houston,  Tex.,  war  anti-mosquito 
work  at,  59 

Hydra  fusca,  211 
viridis,  211 

Hydrochloa  carolinensis,  188 

Hydro philus  obtusatus,  211 


India,  malaria  mortality  in,  6 
Inspection  system,  79,  85 
Inspector,  qualifications  of,  81 
Inspector's  daily  report,  75 

procedure,  86 
Instrument  work  in  drainage,  100 
International  Health  Board,  55,  56, 

60,  63,  69,  76,205,  208 
Iridoprocne  bicolor,  211 
Italy,  malaria  mortality  in,  7 

rice-field  problem,  224 


Jackson,    Miss.,   war   anti-mosquito 
work  at,  59 


Jacksonville,  Fla.,  war  anti-mosquito 

work  at,  59 
Jacksonville,     Tex.,    particulars    of 

anti-mosquito  work  at,  64 


K 


Keltys,  Tex.,  anti-mosquito  work  at, 

57,  58 
Kerosene,  as  mosquito  repellent,  215 

for  oiling,  160 
Knab,  25 
Kress,  Va.,  screening  work  at,  206 


Lake  Charles,  La.,  war  anti-mosquito 
work  at,  59,  205 

Lake  Village,  Ark.,  demonstration 
at,  56,  205,  206,  208,  226 

Larvae,  anatomy  of,  24 

Larvicide,  the  Panama,  161 

Larvicides,  other,  162 

Laveran,  50 

Leathers,  6 

Legendre,  225 

Lemon-juice,  as  a  mosquito  repel- 
lent, 215 

Lenert,  123 

LePrince,  59,  60,  62,  64,  81,  93,  125, 
126,  134,  160,  161,  162, 
166,  170,  213 

Lesticocampa,  211 

Licker-in  wire,  193 

Life,  of  a  mosquito,  IS 
of  a  screen,  203 

Lined  ditches,  125 

Lispa  sinensis,  211 

Little  Rock,  Ark.,  war  anti-mosquito 
work  at,  59 

Livingston,  Tex.,  particulars  of  anti- 
mosquito  work  at,  64 

Logs,  removal  from  streams,  136 

Lonoke,  Ark.,  war  anti-mosquito 
work  at,  59 

Louisville,  Ky.,  war  anti-mosquito 
work  at,  59 

Lucania  parvia,  181 

Lucius  americanus,  183 


INDEX 


245 


Lufkin,  Tex.,  anti-mosquito  work  at, 

57 
Lutzia  bigotii,  211 


M 


Machine  ditching,  117,  14:5 

Macon,  Ga,,  war  anti-mosquito  work 

at,  57 
Macrogametes,  2 
Madagascar,    mosquito    control    in, 

225 
Maintenance  costs,  124 

of  open  ditches,  120 
Malaria  as  a  labor  problem,  8 
census,  68 
characteristics  of,  4 
control  in  United  States,  53 
distribution  of,  5 
economic  significance  of,  7 
history  of  control  at  Panama,  52 
incidence  reports,  67 
mortality  and  morbidity,  6 
parasites,  1 
transmission  of,  1 
versus  yellow  fever  control,  10 
Malvern,    Ark.,   particulars  of  anti- 
mosquito  work  at,  64 
Mansonia  perturbans,  42 
Maps,  97 
Mast,  179 

Materials  and  equipment,  82 
Mauritius,  malaria  mortality  in,  7 
Measures       for       attacking     adult 
mosquitoes,  210 
exterminative,  210 
protective,  214 
Megarhinus  septentrionalis,  211 
Memphis,  Tenn.,  war  anti-mosquito 

work  at,  59 
Methods,  auxiliary,  209 
Metz,  30,  103 
Mierogametocytes,  2 
Mignon,    Ala.,    particulars   of   anti- 
mosquito  work  at,  64 
Millington,        Tenn.,        war       anti- 
mosquito  work  at,  59 
Minnow,  the  spotted  top,  181 
the  star-headed,  181 


Minnow,  the  top,  17.~> 

the  variegated,  ISO 
Mollincsia  latipennia,  183 
Monedula  signata,  211 
Montgomery,       Ala.,       war       anti- 
mosquito  work  at,  59 
Monticello,  Ark.,  demonstration  at, 

56 
Mosquito,  anatomy  of  the,  21 

as  an  annoyance,  14 

breeding  about  homes,  83 

identification  of  the,  20 

in  general,  17 

life-history  of  the,  17 

repellents,  215 

why  it  bites,  19 
Moss,  coon-tail,  188 
Myiochanes  virens,  211 
Myriophyllum,  188 


N 


Naias  flexilis,  190 

Nashville,  Tenn.,  war  anti-mosquito 
work  at,  59 

National    Malaria   Committee,   216 

Navasota,  Tex.,  particulars  of  anti- 
mosquito  work  at,  64 

Negligent  citizen,  the,  87 

Nepa,  211 

Net  for  catching  fish,  186 

New  Orleans  yellow  fever  outbreaks, 
52 

Newport     News,     Va.,     war     anti- 
mosquito  work  at,  59 

Nicaragua,  malaria  mortality  in,  7 

Niter  cake  as  a  larvicide,  162 

Nosema  stegomyia,  211 

Notice,  form  of  official,  88 

Notonecta,  211 

O 

Oil,  distribution  of,  169 

kind  of,  required,  170 

storage  of,  169 
Oiling,  costs  of,  170 

frequency  of,  168 

place  of  in  anti-mosquito  work, 
15S 


246 


INDEX 


Orange,     Tex.,     war    anti-mosquito 
work  at,  59 


Panama  Canal  Zone  Health  Depart- 
ment report,  127 

Panama  Canal  Zone,  malaria  mor- 
tality in,  7 
progress  in  malaria  control  in, 

52 
"swatting"  the  mosquito,  212 

Parallel  system  of  ditching,  140 

Parham,  86 

Pass    Christian,    Miss.,    war    anti- 
mosquito  work  at,  59 

Pennyroyal,    oil   of   as    a    mosquito 
repellent,  215 

Peppermint,   oil  of   as   a   mosquito 
repellent,  215 

Personnel,  80 

Petersburg,  Va.,  war  anti-mosquito 
work  at,  59 

Petrochelidon  lumfrous,  211 

Philippine  Islands,  malaria  mortality 
in,  7 

Physicians,  statistics  from,  67 

Pisobia  pusillus,  211 

Planning  the  inspection  system,  85 
the.  work,  79 

Plants   in    relation    to    fish  control, 
188 

Plasmodia,  1 

Points  requiring  investigation,  209. 
218 

Policy,  questions  of,  73 

Polygonum,  190 

Pool-connecting  system  of  ditching, 
140 

Porto  Rico,  malaria  mortality  in,  7 

Portsmouth,  Va.,  war  anti-mosquito 
work  at,  59 

Progne  subis,  211 

Protecting  homes  in  swamps,  223 

Psorophora  ciliata,  43,  211 

Ptychozoon  homalecephalum,  211 

Publicity,  91 

Pumping,  156 

Pupae,  17,  18,  24,  25 


Q 


Quantico,    Va.,    war    anti-mosquito 

work  at,  59 
Quinine,  for  malaria,  216 

treatment  demonstrations,  216 
versus  anti-mosquito  measures, 
217 


R 


Railroads'  contributions  to  malaria 
hazards,  77 

Rain-water  fish,  181 

Raleigh,    N.   C,  war  anti-mosquito 
work  at,  59 

Rana  palustris,  211 
pipiens,  211 

Ranatra  fusca,  211 

Records,  95 

Reports,  daily,  93 

Rice-field  problem,  the,  224 

Riparis  riparia,  211 

Rizzi,  214 

Roanoke  Rapids,  N.  C,  demonstra- 
tion at,  54 

Rock  Creek  Lumber  Company  anti- 
mosquito  work,  64 

Rose,  6 

Rosenau,  4,  11,  13,  36 

Ross,  6,  50 

Rural  mosquito  control,  219 

protective  demonstrations,  226 

Rusk,     Tex.,     particulars    of    anti- 
mosquito  work  at,  64 


S 


Salt  marsh  ditches,   design  of,    140 
problem,  the,  139 
shrinkage,  156 

Salticus,  211 

San   Antonio,    Tex.,    war  anti-mos- 
quito work  at,  59 

Sayornis  phoebe,  211 

Schizogony,  2 

Screen,  life  of  a,  203 

Screening  campaign,  conduct  of  a, 
204 


INDEX 


247 


Screening  campaign,  cost  of,  205 
of  chimneys  and  fire-places,  202 
of  doors,  197 
of  porches,  201 
of  windows,  200 
place  of  in  anti-mosquito  work, 
195 
Searcy,    Ark.,    particulars    of    anti- 
mosquito  work  at,  64 
Seepage  outcrops,  drainage  of,  104 
Seine  for  catching  fish,  186 
Shaw,  123,  205 
Sheffield,    Ala.,    war    anti-mosquito 

work  at,  59 
Shelby,    Ala.,    particulars    of    anti- 
mosquito  work  at,  64 
Sluice-boxes,  147 
Sluices,  construction  of,  147 

specifications  for  large,  150 
Smart-weed,  190 
Smith,  A.  G.,  129,  130,  131 
Smith,  John  B.,  140 
Smudge,  to  repel  mosquitoes,  215 
Snidow,  199,  204,  206 
Sources  of  aid,  other,  78 
South  Groveton,  Tex.,  particulars  of 

anti-mosquito  work  at,  64 
Spain,  malaria  mortality  in,  7 
Spartanville,     S.     C.,     war        anti- 
mosquito  work  in,  59 
Spirochaeta  culicis,  211 
Spirodella  polyrrhiza,  190 
Sporozoite,  2 

Spotted  top  minnow,  the,  181 
Sprayers,  163 
St.  Louis  &  Southwestern  Railway, 

56,  60,  205 
Stables    as    an   attraction   to   mos- 
quitoes, 214 
Star-headed  minnow,  the,  181 
Statistics,  collection  of,  66 
Straits    Settlements,    malaria    mor- 
tality in,  7 
Stream  re-channeling,  134,  135 
Striped  killifish,  the,  179 
Stromquist,  133 
Sub-aqueous  saw.  the,  193 
Substances  repellent  to  the  mosquito. 
215 


Sub-surface  drainage,  127 
Sun-fishes  in  anti-mosquito  work,  182 
Sunflower    County,    Miss.,    demon- 
stration in,  226 
Survey,  the,  69,  220 
Swamp  home,  protecting  the,  223 
Swamps,  drainage  of,  103,  110 
"Swatting"  the  mosquito,  212 


Table  to  determine  species  of  com- 
mon American  mosquitoes, 
228 
Tachycineta  thalassina,  211 
Tahydromia  macula,  211 
Tanypus  dyari,  211 
Tarbett,  196,  224 
Taylor,  206 
Texarkana,  malaria  cases  at  hospital, 

56,  57 
Texts  for  articles,  92 
Thomasville,     Ga.,     particulars     of 

anti-mosquito  work  at,  64 
Tide-gate,  the  Calco,  153 
Tide-gates,  construction  of,  149 
in  general,  147 
operation  of,  155 
other  types  of,  151 
Tile  drainage  costs,  131 

drains,  127 
Tiles,  placing  of,  130 
Tools  for  hand  ditching,  107,  142 
Top  minnows,  175 
Topography,  need  of  studying  the, 

100 
Transmission  of  malaria,  1 

of  yellow  fever,  8 
Trask,  5 

Trenching  machinery,  117,  118 
Trinitapoli,    Italy,   observations   at, 

214 
Trinity,    Tex.,    particulars   of    anti- 
mosquito  work  at,  64 
Triton  alpestris,  211 

cristatus,  211 
Trypanosoma  culicis,  211 
Tupelo,  Miss.,    particulars   of    anti- 
mosquito  work  at,  64 


248 


INDEX 


Tuscumbia,  Ala.,  war  anti-mosquito 

work  at,  59 
Tyler,  Tex.,  anti-mosquito  work  at, 

57,  58 
Tyrannus  tyrannus,  211 


Vertical  drainage,  131 

Vinegar  as  a  mosquito  repellent,  215 

Virginia  Beach,   Va.,  particulars  of 

anti-mosquito  work  at,  64 
Von  Ezdorf,  55,  212 


U 


United    States    anti-mosquito    war 
work,  58,  59 
Dept.  of  Agriculture,  8 
dengue  cases  and  deaths  in,  11 
malaria  morbidity  and  mortal- 
ity in,  6 
Marine  hospital,   screening  at, 

203 
Public  Health  Service,  7,  11,  53, 
54,  55,  56,  57,  59,  60,  61, 
63,   69,   76,   79,    168,    205, 
208 


W 


Water  gas  tar  as  a  larvicide,  162 

Water  lilies  as  breeding-places,  189 

West  Point,  Miss.,  war  anti- 
mosquito  work  at,  59 

West  Point,  Va.,  particulars  of  anti- 
mosquito  work  at,  64 

Williams,  137 

Wilmington,  N.  C,  war  anti-mos- 
quito work  at,  59 

Work  order,  forms,  87 


Van  Dine,  8,  62 

Variations  in  eggs,  larvae  and  pupae, 
18 

Variegated  minnow,  the,  180 

Vegetation,  removal  of  for  fish  con- 
trol, 186 

Venezuela,  malaria  mortality  in,  7 


Yellow    fever,         mortality        and 
morbidity,  9 
significance  of,  14 
transmission  of,  8 
versus  malaria  control,  10 

Yarnell,  118,  131 


Z 


Zygotes,  4 


CC^  |  in  Engineering 

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